Abrams, J.
The plaintiff Alexander T. Arthurs, a physician licensed by the Commonwealth, seeks judicial review of the decision of the Board of Registration in Medicine (board), revoking his license to practice medicine in the Commonwealth of Massachusetts. The board found that Arthurs prescribed controlled substances for other than a legitimate medical purpose, in violation of G. L. c. 94C, § 19
(a).
The plaintiff claims that (1) the board’s decision is unsupported by substantial evidence; (2) the board erred by basing its decision on one of its adjudicatory opinions decided after Arthurs’s conduct had occurred; (3) the board erred in its treatment of Arthurs’s objections to the recommended decision of a hearing officer; (4) the doctrine of double jeopardy bars the board’s disciplinary proceeding on the ground that Arthurs was acquitted in the Superior Court of charges growing out of the same conduct; and (5) that the disciplinary proceedings are barred on the ground of entrapment. We conclude that the decision of the board should be upheld.
On October 1, 1976, the board issued an order to show cause,
pursuant to G. L. c. 112, § 5,
charging Arthurs with issuing prescriptions for controlled substances for other than a legitimate medical purpose, in violation of G. L. c. 94C, § 19
(a).
Arthurs moved for specification of the charges, and the board detailed its allegations against him in a document entitled “Further Specifications.” In essence, the board charged Arthurs with unlawfully prescribing controlled substances for five persons on fifty-six occasions. Arthurs then challenged the right of the board to deny him a continuance of the disciplinary proceedings during the pendency of criminal charges against him arising from some of the same conduct.
After those proceedings
terminated in the board’s favor, the board held a hearing on its charges. In a “Recommended Decision,” the hearing officer,* ***
who conducted that hearing,
found that Arthurs had prescribed controlled substances for other than a legitimate medical purpose for three persons on numerous occasions.
The hearing officer concluded that in the prescribing of controlled substances, Arthurs failed to meet the minimum standards of proper medical practice suggested in a 1978 opinion by the board.
Matter of Baer,
Adjudicatory Case No. 205 (July 14, 1978).
After Arthurs made written and oral objections
to the recommended decision, the board issued a final order revok
ing Arthurs’s certificate of registration to practice medicine in the Commonwealth of Massachusetts. The board stated that “ [ajfter full consideration of the record and the exhibits, the Board adopts the Recommended Decision as the basis of its decision.”
It further stated that “[ojn the basis of the findings of fact enumerated in the Recommended Decision, and for reasons similar to those set forth in detail in
In the Matter of Arthur E. Baer, M.D., .
. . the defendant did prescribe controlled substances for other than a legitimate medical purpose.”
The specific findings made by the board are that: (1) Arthurs issued, without explanation, repeated refill prescriptions for controlled substances over relatively short periods of time; (2) Arthurs failed to exercise minimum care in preventing persons from obtaining multiple prescriptions from him for controlled substances under different pseudonyms; (3) Arthurs failed to exercise minimum care in obtaining and recording the addresses of patients for whom he was prescribing controlled substances over extended periods of time; and (4) Arthurs repeatedly failed to record an appropriate medical history, and to record an appropriate physical examination, in instances where controlled substances were prescribed.
The board concluded that, “ [f ]rom the extensive evidence submitted, it is clear that [Arthurs’s] behavior was not an isolated incident or oversight, but a pattern of intentional or
negligent practice.”
Arthurs then filed his complaint for judicial review. G. L. c. 112, § 64.*
1.
The- substantiality of the evidence.
Arthurs claims that the decision of the board is unsupported by substantial evidence, and therefore must be set aside. G. L. c. 30A, § 14 (7)
(e).
‘“Substantial evidence’ means such evidence as a reasonable mind might accept as adequate to support a conclusion.” G. L. c. 30A, § 1 (6). Initially, we note the limited nature of our review under the substantial evidence standard. While we must consider the entire record, and must take into account whatever in the record detracts from the weight of the agency’s opinion,
Cohen
v.
Board of Registration in Pharmacy,
350 Mass. 246, 253 (1966), as long as there is substantial evidence to support the findings of the agency, we will not substitute our views as to the facts.
Martin
v.
Director of the Div. of Employment Security,
347 Mass. 264 (1964).
McCarthy
v.
Contributory Retirement Appeal Bd.,
342 Mass. 45 (1961). There must, however, be substantial evidence in the record to support the findings of the board. While the board is free to evaluate evidence in light of its expertise, it cannot use its expertise as a substitute for evidence in the record. We are concerned with how the board arrived at its decision and with the evidence on which it relied.
We summarize the facts found by the board. A.
Charles Jackson and David Jackson.
A black male weighing approximately 300 pounds and standing approximately six feet, three or four inches, tall, established a patient relationship with Arthurs under the names Charles Jackson and David Jackson. On six days this patient visited Arthurs twice, once under each name, and received prescriptions for either Quaalude
or Desoxyn, both controlled substances. The board found as a fact that Jackson was “physically prominent” and that “it would be extremely difficult for him to pass himself under two different aliases to the same doctor.” At the hearing, Arthurs conceded that Jackson was a distinctive looking individual. The board found that Arthurs “knew or should have known” that David and Charles Jackson were the same person.
From the prescriptions and the patient cards in evidence, the board found that Arthurs had prescribed controlled substances on sixteen occasions for David Jackson, and on at least nine occasions for Charles Jackson. All these prescriptions directed the patients to take one tablet daily. The board calculated that over the ninety-two days covered by the first four prescriptions to Charles Jackson, Arthurs issued prescriptions that exceeded the one tablet daily dosage prescribed to that patient by thirty per cent;
over a period of 166 days, Arthurs issued prescriptions to David Jackson that exceeded the directed dosage by forty-five per cent.
Arthurs offered no explanation for the excess in the amount of controlled substances prescribed by him, or for his failure to identify a patient for whom he was prescribing controlled substances.
The facts found by the board also indicate that Arthurs failed to record on a patient card four prescriptions for Quaalude, two for David Jackson and two for Charles Jackson. It also found that six prescriptions for controlled substances issued to David Jackson were recorded on Charles Jackson’s patient card, and that a prescription for Quaalude for one Margaret Jackson was recorded on Charles Jackson’s card.
The patient cards, the board found, showed that Arthurs recorded Charles Jackson’s address on his first visit as 108 Pearl Street, Cambridge, and David Jackson’s address as 108 Pearl Street, Somerville. The first visit of this patient under his two names occurred on two consecutive days. Arthurs used the two addresses interchangeably thereafter.
The board concluded that “ [wjhile it is certainly possible to copy or remember part of an address incorrectly, the extended pattern of using ‘Cambridge’ and ‘Somerville’ interchangeably on the twenty-five prescriptions in evidence for ‘Charles Jackson’ and ‘David Jackson’ raises the question whether Dr. Arthurs here took minimal care to prevent the fraudulent use of controlled substances.”
B.
Gail
Diamond.
Arthurs issued six prescriptions for Quaalude to a patient known to Arthurs as Gail Diamond. Two of these prescriptions were not recorded on the patient card, and on at least one prescription Arthurs used a different address without making a notation of any change of address on the patient card.
Arthurs’s prescriptions directed Diamond to take one tablet daily. Over the forty-nine days covered by the first five prescriptions, the board determined that Arthurs issued prescriptions which exceeded the one tablet daily dosage by 200 %. The board concluded that there might be an explanation for one of the surplus prescriptions,
but not for the others.
C.
Thomas Price.
Thomas Price
was the pseudonym used by a detective from the Massachusetts State Police Diversion Investigation Unit. On Price’s first recorded visit, Arthurs prescribed Nembutal but did not indicate a quantity on the patient card. On Price’s return visit, Ar
thurs noted that “ [pjatient works late as he is a bouncer in a bar room and when he gets home he can’t fall asleep.” There is no notation of a prescription on that date. Arthurs prescribed Nembutal at bedtime to Price on seven subsequent dates, all of which were noted on the patient card, the last with the notation “may repeat if needed.” Arthurs also prescribed Quaalude for him on one occasion. Over the 125 days covered by six prescriptions issued to Price, the board calculated that the number of tablets prescribed exceeded the one tablet daily dosage directed by Arthurs by forty-four per cent.
The patient card for Thomas Price does not show any record of any physical examination during any of his nine visits,
nor any mention of the patient’s present condition after the first two visits; nevertheless, controlled substances were prescribed on all but the second visit.
The findings that prescriptions for controlled substances were not recorded, or were recorded on the wrong patient card, as well as the findings as to the quantity of drugs prescribed at short intervals to patients in excess of Arthurs’s specific directions to take one tablet daily, all support the board’s conclusion that Arthurs prescribed controlled substances for other than a legitimate medical purpose.
“The issuing of additional prescriptions ... at short intervals . . . could [be] found to be inconsistent with accepted medical treatment and support an inference that the prescriptions were not intended to serve a medical purpose.”
Commonwealth v. Comins,
371 Mass. 222, 233 (1976), cert, denied, 430 U.S. 946 (1977). See
United States
v.
Smurthwaite,
590 F.2d 889, 892 (10th Cir. 1979);
United States
v.
Rosen,
582 F.2d 1032,1036 (5th Cir. 1978);
United States
v.
Bartee,
479 F.2d 484, 489 (10th Cir. 1973).
The board also could find that Arthurs prescribed controlled substances not in the usual course of his medical practice and acted other than for a legitimate medical purpose “from evidence . . .
surrounding the facts and circumstances of the prescriptions”
(emphasis supplied).
United States
v.
Rogers,
609 F.2d 834, 839 (5th Cir. 1980). See
United States
v.
Larson,
507 F.2d 385, 387 (9th Cir. 1974). We conclude that on the above facts and circumstances, the board’s decision is amply supported by substantial evidence.
We comment briefly on certain other findings of the board in its decision. The board also found that Arthurs’s recordkeeping, and certain of his medical practices, were deficient in some respects. We cannot consider these findings because there is no substantial evidence in the record to support these findings.
The board, however, argues that since most of the members of the board are experts, the board can use its expertise without the evidentiary basis of that expertise appearing in the record. “This startling theory, if recognized, would not only render absolute a finding opposed to uncontradicted testimony but would
render the right of appeal completely inefficacious as well. A board of experts, sitting in a quasi-judicial capacity, cannot be silent witnesses as well as judges.”
New Jersey Bd. of Optometrists
v.
Nemitz,
21 N.J. Super. 18, 28 (1952). The board may put its expertise to use in evaluating the complexities of technical evidence. However, the board may not use its expertise as a substitute for evidence in the record. “The requirement for administrative decisions based on substantial evidence and reasoned findings — which alone make effective judicial review possible — would become lost in the haze of so-called expertise [if material facts known to the agency did not appear in the record]. Administrative expertise would then be on its way to becoming ‘a monster which rules with no practical limits on its discretion.’”
Baltimore & Ohio R.R.
v.
Aberdeen & Rockfish R.R.,
393 U.S. 87, 92 (1968), quoting from
Burlington Truck Lines, Inc.
v.
United States,
371 U.S. 156, 167 (1962).
If an agency wishes to rely on a fact, that fact must be established by evidence in the record. An agency may introduce technical or specialized facts in the record through expert witnesses, or by taking official notice of facts. G. L. c. 30A, § 11 (5). Whatever method it chooses, the board must make certain that sufficient evidence is in the record for a court to review the evidence on which the agency relies.
As we read the board’s decision, it concentrated on Arthurs’s overprescribing, his failure properly to identify David and Charles Jackson, and the obvious mistakes in the patient cards concerning the prescriptions in evidence. The over-all facts and circumstances established by substantial evidence permitted the board to conclude that Arthurs was not acting for a legitimate medical purpose in prescribing controlled substances. Determinations as to the effect of conduct is essentially a matter of drawing inferences, and an agency’s conclusions based on inferences will not be set aside by a reviewing court unless they are unreasonable. We
conclude that the inferences drawn by the board in this case are reasonable and are supported by substantial evidence.
2.
Reliance on the Baer decision.
Arthurs challenges the revocation of his license on the ground that the hearing officer, and the board, took notice “of general, technical or scientific facts” without notifying him of the materials so noticed as required by G. L. c. 30A, § 11 (5).
He also claims that the board is required to adopt such standards as it promulgated in
Matter of Baer,
Adjudicatory Case No. 205 (July 14,1978), see note 25,
infra,
solely by rulemaking, and that it is not fair to judge Arthurs’s conduct by criteria set forth in an adjudicatory case determined after that conduct had occurred.
In its decision, the board drew inferences from the findings of fact as to Arthurs’s conduct. “[T]he Board is, as is any other trier of fact, accorded the power to draw reasonable inferences from the evidence before it.”
NLRB
v.
Milk Drivers, Local 338,
531 F.2d 1162, 1165 (2d Cir. 1976). “One of the purposes which lead to the creation of such boards is to have decisions based on evidential facts under the particular statute made by experienced officials with an adequate appreciation of the complexities of the subject which is entrusted to their administration.”
American Broadcasting Cos.
v.
Writers Guild of America, West, Inc.,
437 U.S. 411, 433 (1978), quoting from
Republic Aviation Corp.
v.
NLRB,
324 U.S. 793, 800 (1945).
Radio Officers’ Union
v.
NLRB,
347 U.S. 17, 48-49 (1954). The board’s conclusion that Arthurs prescribed controlled substances for other than legitimate medical purposes is a reasonable and permissible inference from the evidence. See
supra
at 308-
309. The board based its holding on the
Baer
decision, which relies on case law,
not on expertise or technical knowledge. See note 22,
supra.
The inferences drawn from the evidence in this case were largely matters of common experience and common sense, not matters of specialized or technical knowledge.
Arthurs next argues that the board should have utilized rulemaking rather than adjudication in establishing standards for determining when a physician unlawfully prescribes controlled substances. We disagree. It is a recognized principle of administrative law that an agency may adopt policies through adjudication as well as through
rulemaking.
SEC
v.
Chenery Corp.,
332 U.S. 194, 201-203 (1947). Accord,
NLRB
v.
Bell Aerospace Co.,
416 U.S. 267, 291-294 (1974);
Maine Pub. Serv. Co.
v.
FPC,
579 F.2d 659, 669 n.14 (1st Cir. 1978). Policies announced in adjudicatory proceedings may serve as precedents for future cases. See
NLRB
v.
Wyman-Gordon Co.,
394 U.S. 759, 766 (1969);
Michigan Wisconsin Pipe Line Co.
v.
FPC,
520 F.2d 84, 89 (D.C. Cir. 1975). Further, “the choice made between proceeding by general rule or by individual,
ad hoc
litigation is one that lies primarily in the informed discretion of the administrative agency.”
SEC
v.
Chenery Corp.,
332 U.S. 194, 203 (1947).
NLRB
v.
Bell Aerospace Co.,
416 U.S. 267, 294 (1974).
We do not think it inappropriate, much less erroneous, for the agency to use an ad hoc method of adjudication in disciplinary cases arising out of a criminal statute which is interpreted on an ad hoc basis by the courts. “It is the merit of the common law that it decides the case first and determines the principle afterwards. ... A well settled legal doctrine embodies the work of many minds, and has been tested in form as well as substance by trained critics whose practical interest it is to resist it at every.step. These are advantages the want of which cannot be supplied by any faculty of generalization, however brilliant . . . .”
Matter of Roche,
381 Mass. 624, 639 n.16 (1980), quoting Justice Oliver Wendell Holmes, Codes, And the Arrangement of the Law, 5 Am. L. Rev. 1 (1870).
Since the board’s decisions are public, see 243 Code Mass. Regs. 1.04: (13) (1979),
the board is not at fault if persons
appearing before it are unaware of its decisions. Of course, it is helpful for the hearing officer to inform counsel of the opinions on which the hearing officer intends to rely. Arthurs had an opportunity
to argue that the inferences from the evidence of overprescribing, the failure to recognize a patient obtaining prescriptions under two names, and the failure to record prescriptions for controlled substances on patient cards, were not reasonable or, even if reasonable, should not be made by the board.
Arthurs also contends that, since the conduct which gave rise to the charges against him took place prior to the
Baer
decision, any reliance on the
Baer
standards is barred as an ex post facto ruling. The short answer is that disciplinary proceedings fall outside the scope of the ex post facto doctrine.
Hawker
v.
New York,
170 U.S. 189, 197 (1898).
Foster
v.
Police Comm’rs,
102 Cal. 483, 492 (1894).
Furnish
v.
Board of Medical Examiners,
149 Cal. App. 2d 326, 330-331 (1957). The
Hawker
court, holding that a State may bar a convicted felon from the practice of medicine by way of legislation enacted after the individual’s conviction, stated, “The State is not seeking to further punish a criminal, but only to protect its citizens from physicians of bad character.” 170 U.S. at 196. Such a law is, rather than ex post facto, simply “retrospective insofar as it determines from the past conduct of the party his fitness for the proposed business.”
Furnish, supra
at 331, quoting from
Foster, supra
at 492. Further, Arthurs’s conduct was criminal under G. L. c. 94C, § 19
(a),
and that statute was in effect prior to the conduct which culminated in discipline. Thus the board did not impose any new substantive liabilities on Arthurs. Cf.
Commonwealth
v.
Klein,
372 Mass. 823, 833 (1977) (new standard of criminal conduct not applied retroactively because defendant not on notice of possible criminality of his conduct). See also
Commonwealth
v.
Lewis,
381 Mass. 411, 418 (1980).
3.
The board’s denial of Arthurs’s objections to the recommended decision.
After the hearing officer filed the recommended decision with the board, the board notified Arthurs of his right to file objections to that decision.
Arthurs then filed written objections and made oral objections to the recommended decision. The board’s, final order, which adopted the recommended decision, noted Arthurs’s objections, but did not specifically address or answer them.
Arthurs argues that the board erred by not providing an adequate statement of reasons for overruling his objections. We disagree. First, while the board is required to afford parties adversely affected by a recommended decision of a hearing officer the opportunity to file objections to the decision, see note 29,
supra,
nothing in the regulations governing the board’s adjudicatory hearings requires the board to respond specifically to those objections. Second, while G. L. c. 30A, § 11 (8),
requires every agency decision to be “accompanied by a statement of reasons for the decision,” that requirement was satisfied in this case by the statement of reasons set forth in the hearing officer’s recommended decision, which the board adopted in its entirety. General Laws c. 30A, § 11 (8), does not specifically require
that objections to a recommended decision be answered or be accompanied by a statement of reasons, only that the agency’s final decision be accompanied by the required statement of reasons. The board’s failure to rebut Arthurs’s objections specifically, therefore, is not error.
Arthurs also argues that it was error for the board to have overruled those objections since the board did not have a copy of the hearing transcript when it made its ruling. The simple answer is that there is no requirement in the State Administrative Procedure Act that agency officials who are to render a final decision must review the transcript before ruling on objections to a proposed decision. Cf. G. L. c. 30A, § 11 (7). Arthurs urges us to impose a rule of procedure on the board. The board is responsible to the public for the discipline of physicians who abuse their obligations and the responsibilities of their profession. Since the board must “provide itself with the flexibility it needed to investigate and to determine whether the public interest requires the revocation of a physician’s license,”
Levy
v.
Board of Registration & Discipline in Medicine,
378 Mass. 519, 526 (1979), we defer to the board’s determination as to how it should proceed as long as its actions are consistent with the requirements of due process and G. L. c. 30A. We decline to impose a rule on the board which might unduly hamper its effective functioning. See
Grocery Mfrs. of America, Inc.
v.
Department of Pub. Health,
379 Mass. 70, 80 (1979).
4.
Double Jeopardy.
Arthurs argues that since he was acquitted in 1977 of charges relating to the issuance of prescriptions to Thomas Price (the undercover officer), and since the indictments as to Charles and David Jackson, and Gail Diamond were continued without a finding and then dismissed, see
Commonwealth
v.
Brandano,
359 Mass. 332 (1971), the principle of double jeopardy bars the board from disciplining him. Arthurs claims that the disciplinary proceedings are punitive, and as such they are barred by the outcome of judicial proceedings. Arthurs argues that, since a person disciplined by a professional board is necessarily
humiliated and disgraced, disciplinary proceedings are essentially a form of punishment. While Arthurs may be correct as to the effect of such a proceeding on a disciplined professional, the purpose of discipline is not retribution but the protection of the public. The board is mandated to police the medical profession, and to take appropriate disciplinary action against those members of the profession “who do not live up to the solemn nature of their public trust.”
Levy
v.
Board of Registration & Discipline in Medicine,
378 Mass. 519, 528 (1979). The fact that discipline is painful does not alter the board’s responsibility to consider a physician’s qualification to practice medicine. The board may make that determination even in cases where the physician prevails in a judicial proceeding. See
Helvering
v.
Mitchell,
303 U.S. 391, 397 (1938);
United States
v.
Naftalin,
606 F.2d 809, 812 (8th Cir. 1979);
Younge
v.
State Bd. of Registration for the Healing Arts,
451 S.W.2d 346 (Mo. Sup. 1969), cert, denied, 397 U.S. 922 (1970);
Strance
v.
Neto Mexico Bd. of Medical Examiners,
83 N.M. 15 (1971).
5.
Entrapment.
Arthurs argues that the conduct of Thomas Price, the Massachusetts State Police Diversion Unit undercover detective, constituted entrapment.
Even assuming entrapment is a defense in a delicensure proceeding, see
Patty
v.
Board of Medical Examiners,
9 Cal. 3d 356 (1973), the record does not support Arthurs’s contention. To show entrapment, a defendant must show some evidence of government inducement, and “[m]ere evidence of solicitation is not enough to show inducement.”
Commonwealth
v.
Thompson,
382 Mass. 379, 385 (1981), quoting from
Commonwealth
v.
Miller,
361 Mass. 644, 652 (1972). Here, there were no lengthy negotiations between Arthurs and Price, nor was there evidence that the govern
ment “went beyond a simple request and pleaded or argued with the defendant.”
Commonwealth
v.
Thompson, supra
at 385, quoting from
Commonwealth
v.
Miller, supra
at 652, quoting from
Kadis
v.
United States,
373 F.2d 370, 374 (1st Cir. 1967). Cf.
United States
v.
Jannotti,
501 F. Supp. 1182, 1193-1203 (E.D. Pa. 1980). Compare
Patty
v.
Board of Medical Examiners,
9 Cal. 3d 356 (1973), with
Kee Wong
v.
State Bar of Cal.,
15 Cal. 3d 528, 531 (1975).
The action is remanded to the single justice with directions to enter a judgment affirming the decision of the board revoking Alexander T. Arthurs’s license to practice medicine.
So ordered.