Full opinion text
VANCE, Circuit Judge: The appellants in this case, Dr. Donald Gold, Patricia Warren, Gary Highsmith, and Opti-Center, Inc., were convicted in the United States District Court for the Middle District of Florida on charges of conspiracy and defrauding the government through the filing of false Medicare claims in violation of 18 U.S.C. §§ 371, 287, and 1001. The appellants challenge their convictions on a variety of grounds, but we find no merit to any of their contentions and therefore affirm the judgment of the district court. I. STATEMENT OF FACTS A. The Medicare — Part B Program The Medicare — Part B program was established by Congress in 1965 to provide supplementary medical insurance benefits for Social Security recipients. Under this program, beneficiaries who pay a $60 annual deductible are entitled to reimbursement for eighty percent of the reasonable cost of covered medical services and supplies. Routine eyewear is specifically excluded from Medicare coverage, but new and replacement prosthetic devices are covered if a physician certifies that the item is a medical necessity. Post-operative cataract ey-ewear is covered by Medicare, although cataract sunglasses are not. Medicare is administered by the Health Care Financing Agency (HCFA), but HCFA does not handle claims submissions and reimbursements directly. In Florida, HCFA has a contract with Blue Cross/Blue Shield of Florida, Inc. (Blue Cross), whereby Blue Cross serves as a fiscal intermediary to receive, adjudicate and pay Medicare — Part B claims submitted to it by Medicare beneficiaries and health care providers. Blue Cross processes these claims in accordance with the instructions supplied by HCFA through its Carrier’s Manual, which explains the mechanics of the Medicare — Part B program and delineates which types of expenses are and are not covered. Claims for reimbursement from Medicare can be made in two ways. When the claim is unassigned, the Medicare beneficiary submits the request for reimbursement himself. The beneficiary also has the option of assigning the claim to the provider of the item or service, who then submits the claim on behalf of the beneficiary and receives reimbursement directly from Blue Cross. In either case, the same claim form is used: standard form 1490. Form 1490 contains such information as the Medicare beneficiary’s name, address, type of illness or injury, date of service, type of service, and the cost of the item or service provided. After the claim is submitted to Blue Cross, it determines whether to make or refuse payment. If an approved claim has been assigned to the health care provider, the reimbursement check is sent directly to the provider. B. The Activities of the Defendants Opti-Center, Inc. was a Georgia corporation engaged in selling retail eyewear that began doing business in Florida’s Tampa Bay area in 1976. Opti-Center had a lease arrangement with Montgomery Ward and operated as the “Montgomery Ward Optical Department” in eight of its stores in and around Tampa. Except for a brief interval in 1980, Columbus optometrist Dr. Donald Gold was the President and majority shareholder of Opti-Center from its inception until its sale to the U.S. Vision Company in 1981. Patricia Warren was Regional Manager for the eight Tampa Bay area stores, with responsibilities that included hiring and firing of personnel, training, coordination, scheduling, and monitoring of inventory. Sue Conway was an optician who started out as the manager of the Opti-Center unit at the East Lake Square Mall in 1978; she was later promoted to the position of district manager in charge of the Dale Mabry unit and two other stores. Gary Highsmith was another optician who joined Opti-Center in April 1980 and became the manager of Opti-Center’s Lake-land store. The evidence presented at the trial established that Dr. Gold was a hard-driving businessman who carefully supervised almost every detail of Opti-Center’s operations. When optician Howard Gilbert applied for a position with Opti-Center in the fall of 1977, for example, Dr. Gold was present at his interview and instructed him in the use of a sales tract that was employed in all of Opti-Center’s stores. Dr. Gold told Gilbert that he should memorize the tract — which was essentially a structured sales presentation designed to overcome any objections a potential customer might have to purchasing eyewear — before reporting to work. Gilbert also testified that Dr. Gold told him that he would expect Gilbert’s store to produce at least $600 a day in sales. Dr. Gold followed through on these initial instructions by making occasional inspection tours of his individual stores. Gilbert recalled that Dr. Gold would usually stop by four or five times a year. He was often accompanied by Patricia Warren, who in her capacity as regional manager made frequent inspection visits. On these occasions, Gilbert reported, they would quiz the opticians and other salespersons on the use of the sales tract and observe their handling of potential customers. If an employee’s knowledge of the sales tract appeared defective, he would be sent home with orders not to return until he had committed it to memory. Dr. Gold and Warren also instructed their salespersons not to wait for potential customers to enter the optical department, but to aggressively seek them out by approaching shoppers as they were passing through the store aisles nearby. Gilbert estimated that “nine out of ten people we sold glasses to were people that were not thinking about buying glasses when they walked into Montgomery Wards’.” Dr. Gold’s obsessive concern for the bottom line was also reflected by his practice of calling the stores at the end of each day to inquire about the sales figures. Gilbert testified that Warren usually called each of the stores three or four times a day as well, and the store manager would be harshly reprimanded and told to do better if sales were down. The pressure that Dr. Gold put upon Opti-Center employees to generate ever-increasing sales figures gradually led the company and its personnel into illegal activity. Opti-Center’s slide into criminality began in the summer of 1979. Gilbert had been transferred to the Opti-Center unit at Clearwater, where he found that it was often difficult to make sales because the senior citizens who made up most of the store’s clientele were usually unable to pay the full purchase price in cash. Gilbert discussed this problem with Warren and suggested that it would be easier to make sales if the company changed its policy against accepting claims on assignment. Dr. Gold approved the change, and the sales figures of the Clearwater store improved dramatically. One of the principal growth areas at the Clearwater unit was cataract glasses. At some point in the autumn of 1979, Gilbert sold a pair of cataract sunglasses on assignment to a customer who had purchased a pair of regular cataract glasses from him shortly before. When Blue Cross subsequently paid on the assignment, Gilbert realized that he could boost his sales figures by urging customers who came into the store to purchase regular cataract glasses to acquire a pair of cataract sunglasses at the same time. There was a slight hitch, however: Blue Cross proved unwilling to pay for more than one pair of glasses when two pairs were submitted on the same claim form. Warren and Gilbert conferred about this problem, concluded that the computer at Blue Cross was misreading the claim form, and decided to start submitting two separate forms with different dates for the two pairs of glasses. This practice of falsifying one of the dates seemed to take care of the problem, and Opti-Center had no further difficulties collecting from Blue Cross on each pair of glasses. Because these simultaneous sales of both regular and dark-tinted cataract glasses— known as “double-cataract” sales by company employees — could bring in as much as $450 from a single sale, they soon became a major focus of Gilbert’s business. He redesigned the sales tract to accomodate the special concerns of cataract customers, and business at the Clearwater store boomed. Dr. Gold and Warren were delighted, and they began urging Opti-Center employees at other stores to emulate Gilbert's techniques. Gilbert testified that Dr. Gold was fully aware of what was involved in the new sales procedure, since he often examined the sales files on his inspection visits and frequently inquired about the high levels of accounts receivable that were generated by accepting so many double cataract sales on assignment. At no time did Dr. Gold raise any objection to this procedure, despite the fact that he had signed a pleading in 1975 acknowledging that he had received and read a communication from the State of Georgia explaining that its state health insurance program was identical to Medicare and including as an attachment section 2130 of the Carrier’s Manual, which explicitly stated that payment could not be made for cataract sunglasses. In addition, at least one Opti-Cen-ter employee with prior experience elsewhere had told Gilbert and Warren in early 1980 that they were wrong about Medicare paying for cataract sunglasses. Nevertheless, Gilbert continued making double cataract sales and soon ventured into other fraudulent practices as well. In addition to spacing out the sales dates on the 1490 forms, Gilbert began changing the prices on glasses that cost the same amount in order to make them appear different from one another. Then he began billing Medicare for more expensive lenses than he had actually provided a customer— such as charging Medicare for bifocal lenses when he had in fact supplied the customer with less expensive single-vision lenses. On some occasions when he had merely changed the lenses within a customer’s existing frames, Gilbert billed Medicare for both the lenses and a pair of frames. He also charged Medicare for the cost of mistakes and re-doing lenses that proved unsatisfactory to customers. Gilbert’s initiative and productivity were duly rewarded by Opti-Center with several raises before he left the company in the autumn of 1980. The techniques that Gilbert had pioneered gradually infected the other Opti-Center stores in the Tampa area as Dr. Gold and Warren put pressure on other employees to emulate Gilbert’s success. When Sue Conway became a district manager in the spring of 1980, Warren urged her to boost sales at her two units by instructing her personnel to make double cataract sales. Gary Highsmith likewise began stressing double cataract sales when he was hired as the store manager of the Lakeland unit in April 1980. When Sue Conway and Warren visited the Lakeland store a month later, Conway examined Hi-ghsmith’s Medicare files (which were located in a drawer labeled “cataract city”) and noticed that he always used the same two procedure codes, the same description, and the same price on the 1490 forms, regardless of what type of glasses he had actually sold. This practice apparently sped processing of the assigned claims, helping to reduce the total of accounts receivable. In addition, the lens descriptions and procedure codes used by Highsmith permitted him to claim the maximum amount ($250) that Medicare refunded on eyewear. Conway explained Highsmith’s practices to Warren and, with her approval, implemented similar procedures at her own stores. When Conway’s units experienced a significant increase in sales, Warren bragged about their success to other Opti-Center employees and urged them to adopt Conway’s procedures as well. Dr. Gold was apparently delighted with the new sales techniques, telling Conway in the summer of 1980 that he wanted Medicare sales to comprise 50% of their business. By the summer of 1980, double cataract sales had become an important source of business at almost all of the Opti-Center stores. Although some of Opti-Center’s employees may have heretofore been genuinely ignorant about the extent of Medicare’s coverage, such claims became less plausible after Blue Cross sent out a letter in June 1980 to all eyewear providers in Florida advising them that Medicare did not cover cataract sunglasses or routine eyewear for which there was no medical necessity. Nevertheless, the fraudulent practices continued. When Opti-Center opened a new store called Tampa Bay Center in the autumn of 1980, fifty percent of its business involved Medicare claims, and over ninety percent of those were double cataract sales. The flood of 1490 forms became so great that a substantial backlog accumulated. Conway sought assistance from Dr. Gold, urging him to hire additional personnel to handle the Medicare paperwork, but he refused. Dr. Gold also complained to Warren that Conway should spend less time filling out forms and more time out on the sales floor. The rapid growth of Medicare-based business at the Tampa area stores required Opti-Center to hire a number of new opticians, some of whom objected to the company’s Medicare billing practices. When Nancy Shepard was hired as an optician in November 1980, she told Warren that Medicare beneficiaries were entitled to only one pair of eyewear per year, and then only if the request was accompanied by a doctor’s prescription. Warren challenged her understanding of the Medicare program, and Shepard replied that this had been the law when she worked for an opthamologist two days before. Warren replied that the law had been changed. Another employee, Debbie Develle, also objected to Opti-Cen-ter’s practice of telling customers that they were entitled to new glasses every year, even without a doctor’s prescription. When Develle’s supervisor told her that her perception of the law was incorrect, De-velle called a toll-free number at Blue Cross in Jacksonville and confirmed that her prior understanding was in fact accurate. When Sue Conway brushed aside this information, Develle promptly resigned. Conway did pass along Develle’s claims to Warren, but the latter took no action. At about the same time Linda Robinson, the manager of the Tampa Bay Center store, likewise became concerned about rumors that billing Medicare for the double-cataract sales was illegal and she also called Blue Cross to confirm her suspicions. Robinson informed Warren of what she had learned, but the company’s only response was to demote Robinson to the position of a “floater”, who shifted between different stores as the volume of business required. Robinson subsequently left the company. Thus, by the autumn of 1980, it was becoming increasingly difficult for company officials to close their eyes to the illegality of Opti-Center’s billing practices. Sue Conway admitted at trial that she had realized as early as August of 1980 that some of the claims were improper. As a result of some information she had come across earlier that summer, Conway had instructed her subordinates that Medicare would pay for routine eyewear. Blue Cross subsequently rejected one of the claims on the grounds that no illness or injury was involved. Since it was company policy not to dispense glasses until full payment was received, this created a problem with regard to customers whose glasses were ready but who might not be able to pay the full amount if their claims were disallowed by Medicare. Conway falsely amended the claims to indicate that the customers were aphakic and resubmitted the claims to Medicare. Conway instructed her employees not to bill Medicare for such sales in the future, and in November of 1980 she confessed to Warren that she “had done some illegal things with Medicare billings.” Warren responded that she did not want to hear about it. In early 1981, however, Conway learned that some of her employees had continued to charge Medicare for routine eyewear. She took this problem to Warren, and they decided — after clearing it with Dr. Gold — to issue some refunds. The refunds appear to have been made primarily in cases where the claims falsely stated that the patient had had cataract surgery or where the glasses were never even ordered for the customer. Conway indicated that no effort was made to match the reasons offered on the refund voucher sent to Blue Cross with the actual inaccuracies on the original claim. Sue Conway initially handled the refund process, but in April 1981 her sister Mary was hired by Warren to take responsibility for the company’s medical insurance paperwork. Warren instructed Mary Conway to refund any orders where the customer had not had cataract surgery, where Medicare had paid two or three times on a single order of glasses, or where Medicare had been charged for glasses that were never made or provided to the customer. Warren told her not to refund amounts paid for cataract sunglasses, lens reworkings, or glasses not based on a prescription, however, Warren also indicated that it was not necessary to provide an accurate explanation on the refund voucher that was sent to Medicare. Instead, Conway was to arbitrarily select one of three different generalizations: overpayment, submitted improperly, and wrong procedure code. Mary Conway then started to work through the files at each of the Opti-Center stores in the Tampa area. She noticed double cataract sales at all of the units, as well as overpayments and billings for routine eyewear. The fraudulent practices were particularly widespread at the Lake-land store, where Gary Highsmith was in charge. Although double cataract sales were supposed to have ceased at all stores in April 1981, Highsmith was still making them when Mary Conway began her examination of the files at the Lakeland store in June of that year. She also noted that there were many cases in the files at the Lakeland store where Medicare had been billed for glasses that were never made, and where the Opti-Center work order was blank because Highsmith had never bothered to obtain a prescription. Conway issued over $6,000 in refunds from the Lake-land store for that reason alone. Hi-ghsmith did not appear particularly surprised or dismayed at the widespread evidence of fraud in his files; Mary Conway testified that he sometimes greeted her holding up his fingers like prison bars in front of his face and joking, “We are all going to go to Alcatraz.” In February 1981, Dr. Gold began negotiations with William Schwartz, President of the U.S. Vision Company, who was interested in purchasing Opti-Center. The negotiations initially faltered because Dr. Gold balked at Schwartz’ request for the company’s books and records. According to Schwartz’ testimony at trial, Dr. Gold asserted that this financial information was merely “academic”, explaining that his company operated very differently from U.S. Vision and that direct comparisons could therefore be misleading. Dr. Gold indicated that he was essentially selling a method of doing business — that rather than relying on advertising or supplying eye examinations as part of its service, “he had devised a method to sell eyeglasses off the aisle of the store,” whereby his employees “hovered on the aisle of the store and convinced the customer to come into the department to get their eyeglasses cleaned” rather than “waiting for the customer to come in and ask for a pair of glasses or order a pair.” Dr. Gold emphasized to Schwartz that his approach required “constant checking on it, frequent calls. He said it took a hands-on type of management to — because you had to worry every hour as to how many people were brought into the department____ [I]t took his constant calls and the use of Mrs. Warren in the store to make sure that the employees did this on an hourly and daily basis.” Dr. Gold urged Schwartz to continue Opti-Center’s focus on cataract sales, noting that this “was especially valuable because instead of a fifty dollar pair of glasses, you might have a two hundred fifty dollar or three hundred fifty dollar pair of glasses generated on the basis of cleaning somebody’s glasses.” Dr. Gold also attributed Opti-Center’s success to its policy of accepting sales on assignment. When Schwartz expressed some concern about the problem of getting customers to pay the deductible or the remaining twenty percent balance, Dr. Gold replied that the trick was to price the glasses high enough so that it became immaterial whether the company ultimately managed to collect on the balance or the deductible. Schwartz and Dr. Gold eventually managed to reach an agreement and the sale of the company was finalized on July 23,1981. Approximately one week before the date of the sale, Warren told Sue Conway that Dr. Gold had called and requested that they remove all of the Medicare records from the eight Tampa area stores, taking care to do so after hours so that no one would know what they were doing. Warren and the two Conway sisters accordingly met at the East Lake store after it closed on Saturday evening. While they were there, Warren received a telephone call from Dr. Gold, and Sue Conway overheard them discussing when they would be removing the records from the various stores. Over the course of the next three or four days, Warren and the Conway sisters collected the records of all sales that had been billed to Medicare and re-filed them in the trunks of Warren’s and Mary Conway’s cars. About a week after the company was sold, Sue Conway visited Warren at home and asked what they should do with the captive Medicare records. Warren called Dr. Gold to find out. When Warren explained why she was calling, Dr. Gold first asked her if anyone else was present. Warren lied and told him, “No, Susie is not here,” whereupon Dr. Gold apparently told Warren to dispose of the records. Conway heard Warren reply, “Don, we can’t just ditch the records,” but he insisted, and further instructed Warren that “he is not to be connected with it in any way, he was not involved, and to not say that he had anything to do with it and just have the records disappear.” Warren and Conway decided that this was just too risky, and the records eventually found their way back to the respective stores. After the sale to U.S. Vision was finalized, Schwartz had his first opportunity to examine the sales records in the Opti-Cen-ter stores in the Tampa Bay area. He was astonished to discover that anywhere from twenty-five percent to forty percent of the sales orders were for cataract patients, a far higher volume than at U.S. Vision’s other stores. Schwartz noticed that many of the cataract sales to Medicare patients involved two pairs of glasses; that in many cases Medicare had been billed for sales of cataract sunglasses or routine eyewear; and that there were instances where glasses were charged to Medicare even though no prescription was obtained. He also found cases where Medicare had. been billed for glasses that were never made or delivered to the customer. Schwartz brought up these apparent irregularities with Dr. Gold, who suggested that some of the forms probably reflected clerical mistakes, while in other cases he defended Opti-Center’s handling of the claims. Schwartz was unpersuaded, and he substantially revised the company’s processing of Medicare claims after the sale to conform to his understanding of the law. Although U.S. Vision continued to utilize Dr. Gold’s sales tract in the months immediately following the sale, the new procedures had a dramatic impact on Medicare-related business at the former Opti-Center stores. “It disappeared,” Schwartz subsequently testified. “There was [sic] virtually no more Medicare sales.” During the eighteen months preceding the sale of the company, in contrast, Medicare billings had totaled $346,000. In the autumn of 1981, the Department of Health and Human Services commenced an investigation into Opti-Center’s Medicare billing practices under the direction of Special Agent Frank Cioffi. This investigation ultimately resulted in the indictment and conviction of Dr. Gold, Warren, Hi-ghsmith, Opti-Center, Inc., and Sue Conway. All except the latter appeal. II. THE ISSUES ON APPEAL A. Adequacy of the Indictment Patricia Warren initially attacks the sufficiency of the indictment with regard to the conspiracy count. Her objections appear to be two-fold: first, that the indictment did not adequately inform her of the nature of the charge against her; and second, that there was a material variance between the overt acts stated in the indictment and the proof actually adduced by the government at trial. We conclude that her claims are without merit. Rule 7(c)(1) of the Federal Rules of Criminal Procedure provides that an indictment “shall be a plain, concise and definite written statement of the essential facts constituting the offense charged.” In general, an indictment need contain only those facts and elements of the alleged offense necessary to sufficiently inform the accused of the charge and to safeguard the accused from double jeopardy. Hamling v. United States, 418 U.S. 87, 117, 94 S.Ct. 2887, 2907, 41 L.Ed.2d 590 (1974). When analyzing challenges to the sufficiency of an indictment, courts give the indictment a common sense construction, and its validity is to be determined “by practical, not technical, considerations.” United States v. Morano, 697 F.2d 923, 927 (11th Cir.1983); United States v. Varkonyi, 645 F.2d 453, 456 (5th Cir. Unit A 1981). The indictment in this case was clearly sufficient to meet this standard. Paragraph 9 of the conspiracy count charged the defendants with knowingly presenting false claims to Medicare; it adequately set forth the elements of the alleged offenses and the nature of the defendants’ criminal scheme, which was further defined in paragraphs 10-19 of that count and in the overt acts listed under paragraph 20. Warren also complains that the government sought to prove her involvement in the conspiracy by relying upon proof of events at trial that were not listed in the overt acts section of the indictment. Properly understood, however, a variance exists where the evidence at trial proves facts different from those alleged in the indictment, as opposed to facts which, although not specifically mentioned in the indictment, are entirely consistent with its allegations. See, e.g., Berger v. United States, 295 U.S. 78, 81, 55 S.Ct. 629, 630, 79 L.Ed. 1314 (1935) (fatal variance exists where indictment charges single conspiracy and evidence demonstrates two different and disconnected smaller conspiracies); United States v. Guthartz, 573 F.2d 225, 228 (5th Cir.), cert. denied, 439 U.S. 864, 99 S.Ct. 187, 58 L.Ed.2d 173 (1978) (fatal variance exists where “an indictment enumerates the particular facts alleged to constitute the element of a charged crime and the proof makes out the elements in a different manner”); Project, Thirteenth Annual Review of Criminal Procedure: United States Supreme Court and Courts of Appeals 1982-83, 72 Geo.L.J. 249, 390-91 (1983). There is no constructive amendment here. Warren’s claim is highly similar to that raised by the appellant in United States v. Malatesta, 583 F.2d 748 (5th Cir.1978), rehearing en banc, 590 F.2d 1379, 1381 (5th Cir.) cert. denied, 440 U.S. 962, 99 S.Ct. 1508, 59 L.Ed.2d 777 (1979). In Malatesta, the court noted that “when the indictment charges a violation of a statute in general terms, proof of acts of the kind described, although those acts are not specifically mentioned in the indictment, does not constructively amend it, at least absent a demonstration that this was, or might have been, prejudicial to the defendant.” Id. at 756. Because Warren was not convicted of an offense other than that alleged in the indictment, United States v. Gonzalez, 661 F.2d 488, 492 (5th Cir. Unit B 1981), nor inadequately apprised of the nature of the charges against her, Berger, 295 U.S. at 82, 55 S.Ct. at 630, she has not demonstrated any prejudice to her “substantial rights” as required by Fed.R.Crim.P. 52(a) and her challenge must be rejected. B. Coconspirator Hearsay Dr. Gold contends that the district court improperly admitted hearsay evidence against him in violation of the requirements established by the former fifth circuit in United States v. James, 590 F.2d 575 (5th Cir.) (en banc), cert. denied, 442 U.S. 917, 99 S.Ct. 2836, 61 L.Ed.2d 283 (1979). He maintains that the government failed to prove he was a member of the alleged conspiracy as required by James, and therefore asserts that he was unfairly prejudiced by the admission of extensive testimony concerning acts and statements by Sue Conway, Gilbert, Warren, Highsmith, and other Opti-Center employees. We find no merit in this claim. The former fifth circuit’s decision in James established a two-step procedure for regulating the admission of testimony under the coconspirator exception to the hearsay rule. First, the trial judge is required to make a threshold determination on admissibility, either at a pre-trial hearing or during the presentation of the government’s case in chief but before the evidence is presented to the jury. At this stage, the court is merely required to find that there is at least enough substantial, independent evidence of a conspiracy to take the issue to the jury, and that there is similarly substantial, independent evidence linking the defendant against whom the evidence is offered to the conspiracy. 590 F.2d at 580-82; United States v. Grassi, 616 F.2d 1295, 1300 (5th Cir.), cert. denied, 449 U.S. 956, 101 S.Ct. 363, 66 L.Ed.2d 220 (1980). If the coconspirator’s extrajudicial statement is admitted into evidence under this procedure, James supplies a further safeguard by requiring the trial judge to reconsider its admissibility before submitting the case to the jury. At this point, the court on motion must determine as a factual matter whether the prosecution “has shown by a preponderance of the evidence independent of the statement itself (1) that a conspiracy existed, (2) that the coconspirator and the defendant against whom the coconspirator’s statement is offered were members of the conspiracy, and (3) that the statement was made during the course and in furtherance of the conspiracy.” James, 590 F.2d at 582; see also Fed.R.Evid. 801(d)(2)(E). If the government has failed to meet its burden under this test, the trial court must then decide whether the prejudice arising from the erroneous admission of the coconspirator’s statement can be cured by striking the evidence and giving a cautionary instruction to the jury or whether a mistrial is necessary. James, 590 F.2d at 582-83. Dr. Gold argues that his conviction must be reversed because the government failed to carry its burden of linking him to the conspiracy by a preponderance of the evidence. On the contrary, there was certainly ample evidence to support the trial judge’s conclusion that the requirements of James had been satisfied. The evidence established that fraudulent practices were widespread at Opti-Center’s stores in and around Tampa, suggesting that these improper claims were not the work of isolated corrupt employees, but of a broader conspiracy. Dr. Gold closely monitored the operations of all of the Opti-Center stores in the Tampa Bay area, calling them almost daily for sales figures and making regular inspection visits to the individual units. He examined the sales records at the units and observed his employees making double cataract sales. Although Dr. Gold had signed a pleading in 1975 indicating that he had read a statement explaining Medicare’s coverage policies with regard to eyewear, he at no time objected to the improper practices he observed. He also displayed a curious degree of sensitivity concerning the Medicare sales records at his company’s Tampa Bay stores. During his negotiations with William Schwartz of U.S. Vision concerning the sale of the company, he initially refused to allow Schwartz to inspect Opti-Center’s records, even though Schwartz indicated that the price he could offer would have to be substantially reduced otherwise. In addition, Warren testified that Dr. Gold called her the week before the sale of the company to U.S. Vision was to be finalized and instructed her to remove all of the Medicare sales records from the stores. There was also other evidence suggesting that Dr. Gold lied to Schwartz about some of his company’s sales practices. For example, Howard Gilbert testified that Dr. Gold was aware of the company’s practice of spacing out the dates on Medicare claims when one customer bought two pairs of glasses at the same time. Although Dr. Gold contended at trial and on appeal that this was done innocently, in order to avoid confusing the computer at Blue Cross/Blue Shield, when Schwartz questioned him about this practice, he responded that these were “accidents”, resulting from lab delay, mistakes, or a mix-up in recordkeeping. Similarly, Dr. Gold suggested to Schwartz that the decline in the company’s sales figures in the spring of 1981 was the product of the recession, when he in fact had reason to know that the decline stemmed from the company’s abandonment of certain improper sales practices and the refunds he had authorized Sue Conway to make. Thus, even without relying on such co-conspirator testimony as Sue Conway’s claim that she heard Dr. Gold instruct Warren to “ditch” the company’s Medicare sales records prior to the sale to U.S. Vision, there was strong independent evidence that a conspiracy to defraud Medicare existed, that Dr. Gold was aware of this conspiracy, and that he went to great lengths to conceal its activities. We therefore cannot conclude that the trial judge erred in finding that the coconspirator testimony met the requirements for admissibility set forth in James. C. Admissibility of Documentary Evidence Dr. Gold and Opti-Center also challenge the trial court’s decision to permit the government to introduce into evidence various sections of the Carrier’s Manual which HCFA supplies to its fiscal intermediaries for use in processing Medicare claims. The appellants contend that these exhibits were wholly irrelevant and immaterial because the Carrier’s Manual was neither a law nor a regulation and there was no direct evidence that Dr. Gold or any other representative of Opti-Center had ever seen the provisions in question. The appellants also object to the admission into evidence of government exhibit 47. This exhibit consisted of a large chart which summarized the fraudulent practices the defendants were alleged to have committed and compared the claims they filed against the amount that, according to the testimony of various government witnesses was properly payable by Medicare in such cases. Appellants charge that the admission of this exhibit was improper because it “permit[ted] the government, in essence, to provide the jury with a typewritten outline of its final argument.” Because the decision to admit or to exclude evidence is a matter for the sound discretion of the trial judge, United States v. Ashley, 555 F.2d 462, 465 (5th Cir.1977), cert. denied, 434 U.S. 869, 98 S.Ct. 210, 54 L.Ed.2d 147 (1980), a ruling by the trial court in favor of admitting relevant evidence cannot be disturbed on appeal unless it is determined that there has either been an abuse of discretion or that the lower court’s decision was clearly erroneous. United States v. Duff, 707 F.2d 1315, 1319 (11th Cir.1983). Because neither of these circumstances is present here, we conclude that the trial court’s decision to admit these exhibits was entirely proper. Under Fed.R.Evid. 401 and 402, the basic test governing admissibility is that evidence is relevant if it has “any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” By this standard, there can be little question that the provisions of the Carrier’s Manual were admissible. The government carefully laid the predicate for the admission of this evidence during its direct examination of HCFA official Curtis Lord. Lord first described the statutory provisions governing the Medicare — Part B program, and then discussed the applicable regulations governing reimbursement under Medicare for prosthetic devices: 42 C.F.R. §§ 405.231 (included items and services), 405.310 (nonineluded items and services), and 405.1634 (requirement of certification of medical necessity). Lord then explained that the Carrier’s Manual was “HCFA’s official explanation of the regulations and the statute. It’s a manual that is a narrative that gives carriers the specificity they need to process claims on a day-to-day basis.” Lord also added that HCFA’s fiscal intermediaries were required to follow the statute, regulations, and the Carrier’s Manual under their contracts with the Department of Health and Human Services, and he indicated that there had been no substantial changes in the provisions of the Carrier’s Manual relating to eyewear in recent years. The government then proceeded to introduce sections 2130 and 2100.4 of the Carrier's Manual into evidence. It should be apparent from this summary that although the government was careful to distinguish the Carrier’s Manual from the statutes and regulations that its provisions explicated, it is equally clear that the Carrier’s Manual directly reflected the interpretation of those statutes and regulations by the government officials who were charged with administering the programs involved. The provisions of the Carrier’s Manual were therefore highly relevant to the issue of what types of claims were properly payable under Medicare, which was certainly one of the key issues in this case. The question whether Dr. Gold or anyone else at Opti-Center was familiar with these provisions relates to an entirely separate issue: whether they had the specific intent necessary to commit the crimes in question. In any event, the government did establish that sections of the Carrier’s Manual or letters that paraphrased its language were in fact sent by carriers to opticians and optical stores. Dr. Gold apparently received such information on at least one or two occasions in the early and mid 1970’s, for example, and a letter explaining the provisions of section 2130 of the Carrier’s Manual — which dealt with coverage for prosthetic devices — was sent to all of Opti-Center’s stores in June 1980. Accordingly, we have no difficulty in concluding that the value of the evidence outweighed the claimed prejudice, and the introduction of these exhibits was proper. The issue of the admissibility of the chart comprising government exhibit 47 can also be disposed of easily. Fed.R.Evid. 1006 provides that “[t]he contents of voluminous writings, recordings, or photographs which cannot conveniently be examined in court may be presented in the form of a chart, summary, or calculation.” Government exhibit 47 consisted of a forty-page chart containing fifteen columns of information. The first thirteen columns contained information derived either from other exhibits received into evidence or from oral testimony. The information in the last two columns reflected HHS Special Agent Frank Cioffi’s conclusions as to what Medicare should actually pay in each instance. Agent Cioffi was properly qualified as an expert witness on Medicare coverage, and the trial court was careful to instruct the jury that the chart “does not constitute any findings by the court and ... it is the government’s contention as to what the basic evidence shows.” Because the evidence summarized by the chart was all before the jury in the form of documentary evidence or witnesses’ testimony and the district judge carefully explained the nature of exhibit 47 to the jury, we cannot conclude that the district court abused its discretion by admitting the chart into evidence. United States v. Evans, 572 F.2d 455, 491-92 (5th Cir.), cert. denied, 439 U.S. 870, 99 S.Ct. 200, 58 L.Ed.2d 182 (1978). D. Admission of Testimonial Evidence 1. Testimony Relating to Medicare Coverage Appellants Dr. Gold and Opti-Center challenge a number of decisions by the trial court relating to the admissibility of testimonial evidence about Medicare billing practices. Specifically, they contend that the district court abused its discretion by permitting HCFA official Lord and HHS Special Agent Cioffi to testify concerning the scope of Medicare’s coverage for prosthetic eyewear; by permitting U.S. Vision President Schwartz to testify that he believed Opti-Center’s Medicare billing practices were improper; and by allowing various Opti-Center employees to testify that they had informed their superiors in the company that its Medicare billing practices did not conform to those employed by other optometrists. We find no merit in any of these contentions. With regard to the testimony of Cioffi and Lord, appellants raise a variety of complaints. They object that there was no showing that the subject matter of their testimony was one as to which the trier of fact might require assistance; that Lord and Cioffi could not properly qualify as expert witnesses under Fed.R.Evid. 702; and that their testimony improperly constituted opinions as to the legal implications of the defendants’ conduct. The implausibility of the first of these contentions is best illustrated by the fact that Dr. Gold’s entire defense turned on the argument that a trained optometrist who had been in the optical business for thirty-five years might not understand what types of eyewear were eligible for Medicare. Appellants’ second objection is equally devoid of merit. A trial judge has broad discretion in deciding whether to qualify a witness as an expert, and his action must be sustained on appeal unless it is manifestly erroneous. See United States v. Costa, 691 F.2d 1358, 1361 (11th Cir.1982). Lord was chief of HCFA’s Coverage and Eligibility Policy Section for the southeastern region and had been working in Medicare for nine years, and Cioffi had received special training concerning Medicare and was a three-year veteran of the Office of Investigations within the Inspector General’s Office of HHS. We therefore conclude that the trial judge was within his discretion in finding that they could qualify as expert witnesses. Nor do we believe that the trial court erred by permitting Lord and Cioffi to testify as to whether particular claims filed by Opti-Center were in their opinions eligible for reimbursement under Medicare. It is well established that Fed.R.Evid. 704 permits a witness to express an opinion as to an ultimate issue that must be decided by the trier of fact. United States v. Miller, 600 F.2d 498, 500 (5th Cir.), cert. denied, 444 U.S. 955, 100 S.Ct. 434, 62 L.Ed.2d 327 (1979). In addition, this court has expressly approved the use of expert legal testimony in a case where an IRS agent “merely stated his opinion as an accountant [with regard to the tax consequences of a transaction], and did not attempt to assume the role of the court.” United States v. Fogg, 652 F.2d 551, 556-57 (5th Cir. Unit B 1981), cert. denied, 456 U.S. 905, 102 S.Ct. 1751, 72 L.Ed.2d 162 (1982); see also United States v. Schafer, 580 F.2d 774, 778 (5th Cir.), cert. denied, 549 U.S. 970, 99 S.Ct. 463, 58 L.Ed.2d 430 (1978); United States v. Milton, 555 F.2d 1198, 1204 (5th Cir.1977). Because the trial judge here was careful to instruct the jury about the weight that should be given expert testimony such as that offered by Lord and Cioffi, we conclude that his decision to admit their opinions was proper. Dr. Gold and Opti-Center also attack the trial court’s decision to permit William Schwartz to testify that the volume of cataract eyewear sales at Opti-Center prior to its purchase by U.S. Vision was “excessive”, and that Medicare-related sales at the Tampa area stores “disappeared” after U.S. Vision revised the procedures for handling Medicare claims to conform with its own understanding of the statutory requirements. Appellants raise a barrage of objections to this testimony, contending that it was irrelevant, prejudicial, and constituted improper “opinion” evidence. We believe that it is self-evident that Schwartz’ testimony was highly relevant to the issue of whether Opti-Center’s practices were proper or improper. Fed.R. Evid. 701 permits opinion testimony by lay witnesses if the opinions offered “are (a) rationally based on the perception of the witness and (b) helpful to a clear understanding of his testimony or the determination of a fact in issue.” Schwartz’ statement that he considered the volume of cataract sales at Opti-Center “excessive” was based on his own examination of the store’s records — he testified that between twenty-five and forty percent of all sales were cataract-related — and his personal experience in the optical business. Because his opinion was based on “first-hand knowledge or observation” and was “helpful in resolving issues” that were critical in this case, Fed.R.Evid. 701 advisory committee note, we conclude that the trial judge did not err in admitting his testimony. Nor do we find merit in the objections raised by Dr. Gold and Opti-Center to the admission of testimony from three former Opti-Center employees — Nancy Shepard, Flossie Gousha, and Debbie Develle— who all testified that they had informed their superiors at the company that its Medicare billing practices did not accord with those used by their prior employers in the optical field. Appellants contend that their testimony constituted hearsay and improper opinion evidence, but these objections indicate that they misperceive the nature and relevance of this testimony. The testimony of these witnesses was important not because they were experts on Medicare, but because they had put their superiors on notice that there was reason to question whether Opti-Center’s billing practices were in compliance with the law. Their testimony was therefore useful because it established that the conspirators had reason to know that their activities were illegal; it was not admitted to prove that the interpretation these witnesses had of the Medicare program was necessarily the correct one. 2. Use of Rebuttal Testimony Appellant Warren objects to the government’s presentation of rebuttal testimony against her by Mary Conway and Michael Covington. Covington testified on rebuttal that he had told Warren in June of 1981 about a newspaper article he had read concerning “someone in the medical field [who] had come into some trouble for not collecting the twenty percent” deductible a Medicare patient was supposed to pay. Opti-Center had generally not billed its Medicare customers for this amount. Mary Conway testified on rebuttal that in June or July of 1981, Warren instructed her to alter Opti-Center’s internal records to indicate that the company had in fact been billing its customers for their required contribution. Appellant Warren asserts that this testimony was improperly admitted because it was new evidence that did not rebut anything she had presented in her defense. In fact, however, Warren had flatly denied on cross-examination that she ever discussed such a report with Covington. The purpose of rebuttal evidence is “ ‘to explain, repel, counteract, or disprove the evidence of the adverse party,’ ” United States v. Delk, 586 F.2d 513, 516 (5th Cir.1978) (emphasis omitted) (quoting Luttrell v. United States, 320 F.2d 462, 464 (5th Cir.1963)), and the decision to permit rebuttal testimony is one that resides in the sound discretion of the trial judge. Geders v. United States, 425 U.S. 80, 86, 96 S.Ct. 1330, 1334, 47 L.Ed.2d 592 (1976); United States v. Sadler, 488 F.2d 434, 435 (5th Cir.), cert. denied, 417 U.S. 931, 94 S.Ct. 2642, 41 L.Ed.2d 234 (1974). We find no error in the district court’s decision to permit Covington and Conway to testify in response to Warren’s earlier statements, and we believe that the trial judge’s refusal to permit Warren to re-take the stand was also within the permissible scope of his discretion. E. Reading of Highsmith’s Grand Jury Testimony During the presentation of its case- in chief, the government sought to offer defendant Highsmith’s grand jury testimony into evidence against him in order to establish that he had engaged in double cataract sales and other allegedly illegal practices when he worked for Opti-Center. His co-defendants Warren and Dr. Gold raised objections based on the sixth amendment’s confrontation clause, because Highsmith had asserted in his testimony that his sales practices were based on the instructions he had received from his superiors in the corn-pany. The trial judge decided to delete certain questions and answers from the transcript in order to avoid possible prejudice to Highsmith’s co-defendants. Hi-ghsmith objected, contending that the excision of these passages distorted his testimony and would leave the jury with the false impression that he had committed these allegedly improper acts on his own initiative. While recognizing that Fed.R. Evid. 106 permits the trial judge to decide whether “fairness” requires that a recorded statement must be offered in its entirety, Highsmith contends that the trial judge erred in this instance. He argues that the deleted testimony was essential to his defense that he was merely acting in accord-anee with company policy, whereas the potential prejudice to his co-defendants was slight because the challenged testimony was merely cumulative of that already offered by Gilbert and Sue Conway. We find no merit in Highsmith’s argument. This court has refused in several cases to find that a trial judge erred by deleting portions of a confession that implicated a co-defendant before it was read to the jury, see, e.g., United States v. Kersh-ner, 432 F.2d 1066, 1071 (5th Cir.1970); Posey v. United States, 416 F.2d 545, 551 (5th Cir.1969), and we see no reason that we should be more inclined to trespass upon the trial judge’s discretion in this context. In any event, Highsmith’s claim that he was prejudiced by these deletions , i . , , , ultimately rests upon a novel and untena- ,, ,,, , , , , ,,, ble argument: the assertion that he should ,. . . i , , escape liability for his criminal acts be- , , „ ,, . . , cause he was simply following the mstruc- „ ,. . TI7 ... tions of his company superiors. We will ., ... , , .,. ,, consider this argument m more detail m the section P., infra. J . F. Jury Instructions Dr. Gold, Opti-Center and Highsmith each raise various objections to the jury charge employed by the trial judge. Although a defendant is entitled to have the court instruct the jury on the theory of the defense, provided it has some foundation in the evidence and legal- support, United States v. Terebecki, 692 F.2d 1345, 1351 (11th Cir.1982), the district court has broad discretion in formulating its charge as long as the charge accurately reflects the law and the facts. United States v. Borders, 693 F.2d 1318, 1328-29 (11th Cir.1982), cert. denied, 461 U.S. 905, 103 S.Ct. 1875, 76 L.Ed.2d 807 (1983). A trial judge’s refusal to give a requested instruction constitutes reversible error only if (1) the instruction is substantively correct; (2) it was not substantially covered in the charge actually delivered to the jury; and (3) the failure to give it seriously impaired the defendant’s ability to present an effective defense. United States v. Walker, 720 F.2d 1527, 1541 (11th Cir.1983), cert. denied, — U.S.-, 104 S.Ct. 1614, 80 L.Ed.2d 143 (1984). We conclude that none the objections raised by the appellants satisfies this standard, 4- Br' G°ld Dr- Gold complains that the trial court erred not his requested instructions 15, 16, 17, 18, and 19, and asserts that the instruction on specific intent employed by the trial court was incorrect under United States v Satterfield, 644 F,2d 1092 (5th Gir‘ Umt B 1981)' He also contends that the tnal ^ gave an ^ruction that improperly shifted the burden of Pro°f and was wlth°ut, evidentiary afPort Gold s requested instruction U'S-C' § «« ^lch no payment may be made under Medicare _ * d . ...2 J . . r , • , Part B for items and services ... [which] , .. „ J are not reasonable and necessary for the . , , „ ... . . diagnosis or treatment of illness or injury ® . ,, » „ , or to improve the functioning of a mal- „ , , , , „ . • .i formed body member.” The trial judge f refused to use this instruction because he „ .. ,, ,. . , , . , . felt it would be inappropriate to single out «one isolated statute” for special attention in the charge, noting that there had been extensive expert legal testimony in the case during which the defense could have brought the statutory provision in question to the attention of the jury. We do not believe this was an unreasonable position for the trial judge to take, particularly since the basic point addressed by the provision — that payment under Medicare can be made only for expenses that are a medical necessity — had been brought out in the testimony of various witnesses and was not a subject of real dispute in the case. The issues that were in controversy were (1) whether Dr. Gold was aware of the sales practices of his subordinates and (2) whether sunglasses for cataract patients were a medical necessity. Dr. Gold’s counsel was free to argue the second point in his summation to the jury and he in fact did so; we therefore cannot conclude that Dr. Gold suffered any prejudice as a result of the denial of this instruction. For similar reasons, Dr. Gold’s proposed instruction 17 was also rejected by the trial court. This instruction was based on the language of 42 C.F.R. § 405.232c, which provides that “[t]he prescription or order of a doctor of optometry will be accepted as evidence of the medical need for prosthetic lenses.” Dr. Gold contends that this instruction was critical to the theory of his defense, reasoning that this provision indicates that no new prescription is necessary in order to supply cataract eyeglasses to a Medicare patient and to subsequently claim reimbursement from Medicare. This is a debatable construction at best, and the proper way to have brought this interpretation to the jury’s attention would have been to raise it during the cross-examination of Curtis Lord, who testified extensively about other federal regulations that are relevant to Medicare eligibility. Nevertheless, Dr. Gold’s counsel did present this interpretation of the regulation to the jury during his closing argument, and we therefore do not believe that the trial judge’s refusal to deliver this instruction in any way prejudiced Dr. Gold’s defense. Dr. Gold’s requested instructions 16 and 18 both stressed that the Carrier’s Manual and the circulars explaining Medicare eligibility that Blue Cross occasionally sent out to health care providers were not law and that the defendants were not presumed to have knowledge of them. The nature of the Carrier’s Manual and the newsletters were adequately set forth in the testimony of various witnesses, however, and defense counsel argued the notice issue quite thoroughly in their summations to the jury. Because it was ultimately up to the jury to decide as a factual matter whether the defendants’ protestations of ignorance were credible, we cannot hold the trial judge in error. Dr. Gold also objects to the trial court’s rejection of his proposed instruction 19, which stated: If you find that a defendant in this case was ignorant, or had no knowledge, of any law or regulation, then that defendant cannot be found guilty. If, after considering all of the evidence, you have a reasonable doubt as to whether a defendant knew of a particular law or regulation, then that would mean that the government had not proven specific intent beyond a reasonable doubt. The trial judge instead gave the following charge: It is not necessary for the government to prove that a defendant knew that a particular act or failure to act is a violation of law. However, evidence that a defendant acted or failed to act because of ignorance of the law is to be considered by the jury in determining whether or not that defendant acted or failed to act with specific intent, as charged. Although Dr. Gold asserts that the language of his proposed instruction was approved by this court in United States v. Satterfield, 644 F.2d 1096, his version of the instruction is far broader. Its suggestion that ignorance “of any law or regulation” (emphasis added) would be a complete defense is a misreading of Satterfield and a misstatement of existing law. This court and others have held that the defense of ignorance of the law is a consideration in specific intent crimes, but none has gone so far as to invalidate the presumption of knowledge of the law. We conclude that the instruction used by the trial court accurately stated the law. Its language essentially tracked that of the model charge suggested on this issue in Devitt & Black-mar, Federal Jury Practice and Instructions, § 14.01, which was at least implicitly approved by this court in United States v. Schilleci, 545 F.2d 519, 523-24 (5th Cir.1977). See also United States v. Davis, 583 F.2d 190, 194 & n. 3 (5th Cir.1978). It is well established “[although a defendant may request a specific instruction the court is not obligated to use the exact wording of the proposed instruction as long as the words chosen clearly and accurately state the proposition being requested.” United States v. Duff, 707 F.2d 1315, 1320-21 (11th Cir.1983). In this ease the trial judge’s charge was clearly a correct statement of the law and reflected his awareness of the need to strike a proper balance between the government and the defense. We find no fault with his choice. Finally, Dr. Gold contends that the trial judge erred in his instructions to the jury on the issue of whether the defendants could be found to have knowingly acted in violation of the law. The contested instruction states: It is not [sic] necessary that you find beyond a reasonable doubt that any act you may have found to have been committed by a defendant was done or committed knowingly. In this connection, however, you are instructed that a person who makes a claim or a statement or causes a claim or a statement to be made with reckless disregard for the truthfulness of the claim or statement and with a conscious purpose to avoid learning the knowledge of the claim or statement is deemed to have knowledge of the claim or statement and its truthfulness or lack thereof. Dr. Gold asserts that this instruction was erroneous because the “not” in the first sentence improperly shifted the burden of proof to the defendants and because there was no evidentiary basis for the instruction on “conscious avoidance,” as required by the courts in such cases as United States v. Garzon, 688 F.2d 607, 609 (9th Cir.1982), and United States v. Murrieta-Berjarano, 552 F.2d 1323, 1325 (9th Cir.1977). We find neither contention persuasive. While it is true that it would have been incorrect for the instructions to state that the jury did not have to find beyond a reasonable doubt that the defendants had committed their criminal acts knowingly, there is some dispute among the attorneys involved in this ease as to whether the offending word “not” was actually used or is simply a court reporter’s error. It apparently did not appear in the draft of the court’s instructions that was distributed to counsel for their examination prior to closing arguments, and none of the defense counsel raised an objection on this point after the instructions were read to the jury. Even if the judge’s clerk did inadvertently include the word “not” while reading the instructions to the jury, however, we believe that this error was clearly harmless beyond a reasonable doubt. Fed.R.Crim.P. 52(a); Chapman v. California, 386 U.S. 18, 24, 87 S.Ct. 824, 828, 17 L.Ed.2d 705 (1967). The trial judge here permitted the jury to take a copy of the instructions (in