Mrs. Radvilas (hereafter Radvilas) filed a complaint in the Superior Court against Stop & Shop, Inc. (S & S), and three of its employees alleging discrimination against her. Count I, in very general terms for the most part, asserted violations (sex and age discrimination) by S & S of G. L. c. 151B. Count II, in similar manner, charged discrimination against Radvilas in violation of the Age Discrimination in Employment A*ct of 1967, 29 U.S.C. §§ 621 et seq. (1976), and also under G. L. c. 12, § 111. Count III charged pay practices discriminating against her under the Equal Pay Act, 29 U.S.C. §§ 206 (d) and 215 (a) (1976). At the close of Radvilas’s evidence, a judge of a Juvenile Court, sitting in the Superior Court by designation, allowed the defendants’ motions for directed verdicts. Radvilas appeals from judgments for the defendants and from the denial of her motion for a new trial. We conclude that the trial judge should not have granted S & S’s motion for a directed verdict for it on Counts I and II. Otherwise the judgments are affirmed. The jury, on the evidence, would have been warranted in finding the facts summarized below.2
Radvilas (at trial in 1983, 54 years old) was hired by S & S in 1968 as a “warehouse worker” at S & S’s distribution center in Braintree. Her job at first was as one of a small number of employees receiving orders from S & S’s retail stores and distributing garments to them. She then “went on to receiving.”3 She would “size the garments and hang them.” She was a re*433ceiver until May, 1977, when she was made a grade 21 employee and a full-time supervisor assigned to the “part-time shift”.
Radvilas worked in “the soft-lines area” and “took care of’ that area on the part-time shift (as the only supervisor in that area) from 5 p.m. to 10 p.m., with the assistance of Frank Martin, a shift leader (grade 22) when she needed help. There were, on the same shift, Dan Devine, supervisor of “the soft lines, bulk area,” and Alfred Bortolotti, supervisor of “the dock area.”* **4
In June, 1977, James Joyce came from the Readville facility to be assistant to Connor Maguire, then manager of S & S’s Braintree facility. Shortly after Maguire introduced him to Radvilas, apparently before she was made a supervisor, Joyce made to her a coarse remark and occasionally other remarks of an offensive character.5 Radvilas testified that she, because *434“ashamed,” did not report the precise first remark to Maguire or to other supervisors. When on one occasion she complained to Maguire about Joyce’s manners, Maguire said that it was necessary to give Joyce time to adjust to a new area and that he was sure “in time . . . Joyce will adjust.” During the first week after Radvilas had been promoted to supervisor, Maguire called Joyce and Radvilas to his office and asked “Joyce if he would help . . . [her] rather than degrade . . . [her] and hinder” her on her job. Joyce replied that Radvilas “was doing the best . . . [she] could” and “agreed that he would try to make . . . [her] job easy.” Radvilas testified that, as a result, there was no drastic change in the situation. Other complaints of allegedly improper or discriminatory treatment are summarized in the margin.* ***6
In October, 1978, Radvilas applied to Pavek, the district distribution manager of the Braintree, Readville, and New Haven warehouses, for transfer to fill a prospective vacancy on the day shift (7 a.m. to 3 p.m.) as “bulk” supervisor. Pavek made “no comment” on her inquiry but “listened.” She testified that she had been “doing that job at night.” The position was filled (in June, 1979, while she was on vacation) by Frank *435Lessard. He was a man of about thirty-seven, who “had worked in hard lines” for at least one well-known company apparently owning similar warehouse facilities. The transfer would have involved for Radvilas no difference in pay or benefits but different, longer hours of work. She never spoke to Pavek about the failure to appoint her but did speak to Frank Martin (grade 22) who had been her shift leader at night. He was the only supervisor, so long as Radvilas worked for S & S, who had “requested day [work] and got it.”
Radvilas received various reviews of her work as supervisor, one after about six months and two in 1978. Both 1978 reviews described her, under the heading of “Overall Evaluation,” as having overcome the obstacle of being the first woman supervisor, “a fact not accepted too well by some people who doubted she could do the job.” One version of this appraisal, signed only by Maguire and Joyce, then described her as having “done an extraordinary amount of training . . . [of] employees so that” her “shift is extremely efficient,” as having “become an excellent supervisor,” and as having “proved a woman can do the job as well as any man or better.” The later review deleted this complimentary language and substituted, “She has done well in any task assigned to her and is rapidly becoming a good supervisor.”7 Both appraisals stated, “The biggest challenge Phyllis [Radvilas] will face ... is the ability to adjust to any situation that confronts her while performing her supervisory duties.”8
*436Maguire retired on July 27, 1979. On the following Monday, Nee (Maguire’s successor) became manager of the warehouse. The supervisors were told “that there would be extended hours for the rest of the week” because the warehouse was “exceptionally busy.” The supervisors were to be “working in the second shift from one-thirty [p.m.] to” midnight. Radvilas left the warehouse at 10 p.m. because (among other reasons) she had not brought an extra lunch with her. Bortolotti and Cullen, the other supervisors, as far as Radvilas knew, worked until midnight. Radvilas testified that she had not been given advance notice of the change in schedule. Either on that day or the next, she talked with Nee and Bortolotti and complained about various grievances9 and “refused to work those hours along side the other supervisors . .. [who] were [she claimed] making more money.” Nee told Radvilas “that all supervisors were expected to work the same hours.” She told him “[t]his was unfair” and that she “had no intention to work under those terms.” She then said, “You can take the job and shove it but you will never hear the end of it,” and she left the facility.
That afternoon Capozzi (see note 8, supra) and his secretary came to her apartment.10 Radvilas requested “a meeting with *437someone higher up in” S & S and Capozzi set up a long meeting with Donagan (see note 8, supra), at which Radvilas told them her grievances.11 There was a second meeting at which both sides of her complaints were discussed. She said that she would go back to S & S only if she were paid $19,000 for nights and $18,500 for days, and S & S, “didn’t come up with anything” with respect to what she had asked. She then added, “But we would have compromised.”
The trial judge admitted in evidence against Joyce (who had not been summoned in behalf of Radvilas) certain answers filed by Joyce to Radvilas’s interrogatories.12 The judge ex-*438eluded part of Joyce’s answer to an interrogatory which asked the names, addresses, and salaries, for each of the years 1977 through 1980, of all male supervisors. Joyce had listed these and had shown the grade of each such supervisor. Only a few grade 20 employees were thus listed. The others ranged at least from grade 21 to grade 25. The exhibit showed for each listed supervisor only the job title (usually not very informative), the facility at which the supervisor worked, the supervisor’s grade, and the dates and amounts of salary changes. There was no showing in the answer of the duties and responsibilities of any position, of the prior experience and training of any listed supervisor, or of the hours during which the supervisor worked.
No foundation was laid for the propriety of a comparison between (a) the scanty description in the record of Radvilas’s duties, responsibilities, experience, activities, and working conditions with (b) the same aspects of the work and qualifications of any male supervisor. No testimony was offered as to what the employment grades in S & S’s compensation structure (e.g., 20, 21, 22, and above) meant or implied or what significance and salary effects S & S gave to longevity within any particular grade. The judge excluded the answer at least until Radvilas’s counsel was prepared “before the trial is ended ... to compare apples with apples, rather than apples with oranges.” He pointed out also that a company may reasonably come to the conclusion that certain supervisory capacities and positions are more important than others.13
1. The principles governing whether there can be recovery, based upon sex discrimination, under G. L. c. 151B are discussed in Wheelock College v. Massachusetts Comm. Against Discrimination, 371 Mass. 130 (1976), which (at 135 & n.5) *439adopts essentially the procedural requirements of McDonnell Douglas Corp. v. Green, 411 U.S. 792, 802 & n.13 (1973). Although the McDonnell Douglas case involved alleged racial discrimination, similar principles govern cases of sex (and old age) discrimination under G. L. c. 151B. See Smith College v. Massachusetts Comm. Against Discrimination, 376 Mass. 221, 229 (1978). Under the McDonnell Douglas case (at 802), if the party alleging that he or she is the victim of discrimination establishes a prima facie case (the elements of which are discussed below), that preliminary proof causes a shift to the employer of the burden to come forward with evidence to show that its allegedly discriminatory decision was based on some legitimate, nondiscriminatory reason. See Trustees of Forbes Library v. Labor Rel. Commn., 384 Mass. 559, 565-567 (1981); Furnco Constr. Co. v. Waters, 438 U.S. 567, 576-578 (1978). The “burden of persuasion remains with the employee, who must prove by a preponderance of evidence that the asserted lawful reason was not the real reason for the” decision (see the Forbes Library case at 566) or that the employer’s practices were a pretext for discrimination. See generally Schreiber, Massachusetts Employment Discrimination Law 63 Mass.L.Rev. 247 (1978).
The present case, of course, is not one of alleged discrimination in connection with original employment but asserts discrimination in connection with either a desired transfer or a promotion.14 “Adjusting the McDonnell formula to cases of discriminatory refusal to promote [or to transfer] is relatively simple.” See Bundy v. Jackson, 641 F.2d 934, 951 (D.C. Cir. 1981), where it was said also that, in a promotion situation, “to make out a prima facie case the plaintiff must show that she *440belongs to a protected group,- that she was qualified for and applied for a promotion, that she was considered for and denied the promotion [or transfer], and that other employees of similar qualifications who were not members of the protected group were indeed promoted at the time the plaintiff’s request for promotion was denied”. Applying these principles to Radvilas, we consider principally15 her application for transfer to the day shift post of supervisor of the bulk area.
Radvilas did show that, as a woman and as a person over forty years of age, she was a member of two protected groups. She showed that she had applied to Pavek for the transfer to day work and that presumably he had considered her for transfer. She was not given the transfer. She showed that Lessard, a male under forty, was appointed to the post. There are, however, two significant questions relating to whether she made out a prima facie case of discrimination against her because of the appointment of Lessard: (a) Did she establish what the duties, responsibilities, and qualifications for the post were?16 (b) Did she show that she was qualified for the transfer?
There was no proof whether the day job of a full-time bulk area supervisor was the same as the evening work by Radvilas *441(as supervisor of the part-time shift) on unfinished bulk area work left by or which came in after the day shift. The record, indeed, contains no clear description of what was done in the bulk area at any time, day or night. The evidence of Radvilas’s qualifications for the day-time bulk area job lies principally in her own statements17 and in her two 1978 job appraisal reviews, see notes 7 and 8, supra, and related text of this opinion. That evidence gains no perceptible support from Radvilas’s testimony about her grievances (see nn. 5, 6, 9, but compare n. 11).18
We recognize that “the burden of establishing a prima facie case of disparate treatment is not onerous.” Radvilas was bound to “prove by a preponderance of the evidence that she applied for an available position for which she was qualified but was rejected” in circumstances which give rise to an inference of unlawful discrimination. See Texas Dept. of Community Affairs v. Burdine, 450 U.S. 248, 253-254 (1981). The judge did not rule expressly that Radvilas had not made out a prima facie case. He directed a verdict for the defendants after Radvilas had rested her case on the merits.19
*442We regard it as a close question whether Radvilas, on this somewhat disorderly record (see nn. 2, 3, 9), has established a prima facie case of sexual discrimination under the principles of the McDonnell Douglas opinion. The proof of discrimination against her based on sex consists essentially of the facts that she was not transferred to the vacant daytime job for which she had applied and that a man was appointed. All her proof suffers (see note 3, supra) from the failure to prove in explicit fashion what the qualifications for and the responsibilities of the daytime job were and what in fact Radvilas’s own duties and responsibilities had been in her former job. Taking into account, however, particularly the language of her later 1978 appraisal (quoted, note 7, supra), we think enough was shown to permit an inference of her qualification to perform in the daytime the indefinitely described functions of the bulk area which she for a period had performed at night.
Obviously the judge would have been wiser to deny the motions for directed verdicts, to hear S & S’s evidence of the reasons for its decision, and to submit the case to the jury. See Soares v. Lakeville Baseball Camp, Inc., 369 Mass. 974, 975 (1976); Cort v. Bristol-Myers Co., 385 Mass. 300, 304 n.4 (1982). Compare Kalivas v. A. J. Felz Co., 15 Mass. App. Ct. 482, 486 (1983). Then, in the event of verdicts for Radvilas, he could have granted judgments n.o.v. if he then regarded all the evidence, including that produced by S & S (when the burden shifted to it of providing a nondiscriminatory explanation of its decision), as insufficient to satisfy her ultimate burden of persuasion. Because at least the minimum proof of sex discrimination required for a prima facie case under the McDonnell Douglas decision was present, it was error to direct a verdict for S & S on that issue.
With respect to the cases against the individual defendants, we think that, in the absence of proof whether and to what extent any one of them contributed to the allegedly discriminatory decision affecting Radvilas, the directed verdicts for them on this issue were proper. Whatever they did was not shown to be other than in performance of their duties for S & S. The proof was insufficient to constitute a prima facie case against any one of them.
*4432. Other than the fact of the 1979 appointment of Lessard (grade 22), then about thirty-seven years old, rather than Radvilas (grade 21 and in her late forties) to the post of day supervisor of the bulk area, no evidence tends to show age discrimination against Radvilas. No circumstantial evidence (except one rude remark by Joyce about the women working with Radvilas as the “change of life people”) appeared to have any relation whatsoever to employees’ ages. There was no showing that Radvilas, in any aspect of her employment, was treated differently from any other employee because of her age. Nevertheless, our conclusion that Radvilas had made out a prima facie case of sex discrimination seems controlling with respect to age discrimination. She (as a woman over forty and thus a member of a protected class) showed (a) that she was qualified for appointment to the daytime post and was not appointed, and (b) that a man under forty was appointed. This proof seems to satisfy the McDonnell Douglas principles about what constitutes a prima facie case. Those principles appear to be applicable to age discrimination as well as to race and sex discrimination. Also the principles and procedures applicable to age discrimination under G. L. c. 15IB and under 29 U.S.C. §§ 621 et seq. (1976), appear to be generally comparable. See e.g., Rock v. Massachusetts Commn. Against Discrimination, 384 Mass. 198, 204-205 (1981). Loeb v. Textron, Inc., 600 F.2d 1003, 1011-1018 (1st Cir. 1979); Riley v. University of Lowell, 651 F.2d 822, 823-824 (1st Cir. 1981); Stendebach v. CPC Intl., Inc., 691 F.2d 735 (5th Cir. 1982), cert. denied, 461 U.S. 944 (1983); Pena v. Brattleboro Retreat, 702 F.2d 322, 323 (2d Cir. 1983); Massarsky v. General Motors Corp., 706 F.2d 111, 117-120 (3d Cir. 1983). See also Lovelace v. Sherwin-Williams Co., 681 F.2d 230, 239, 243-244 (4th Cir. 1982). Accordingly, we conclude that it was error to direct a verdict for S & S on so much of count I as alleged age discrimination and on count II under 29 U.S.C. §§ 621 et seq. (1976). For essentially the reasons already stated in part 1 of the opinion, we conclude that the evidence of particular actions by the individual defendants severally was insufficient to establish a prima facie case of age discrimination against any one of them.
*4443. Radvilas has not established under count III of her complaint and 29 U.S.C. §§ 203-216 (1976), that S & S paid a higher rate of compensation to any particular supervisor20 for equal work on any job requiring “equal skill, effort, and responsibility . . . performed under similar working conditions.” See Corning Glass Works v. Brennan, 417 U.S. 188, 195 (1974);21 Campbell v. Von Hoffman Press, Inc., 483 F. Supp. 218, 221 (W.D. Mo.), affd. per cur. 632 F.2d 69 (8th Cir. 1980). Jacobs v. College of William & Mary, 517 F. Supp. 791, 795-796 (E.D. Va. 1980), cert. denied, 454 U.S. 1033 (1981), where the proof of requirements of posts under comparison was much more complete; Sullivan, The Equal Pay Act of 1963: Making and Breaking a Prima Facie Case, 31 Ark.L.Rev. 545,559-583 (1978). See also 29 Code of Federal Regulations, §§ 800.100 et seq., especially §§ 800.119-800.123, 800.125-800.132, 800.142-800.144 (1983). Radvilas has not proved what supervisory positions involved substantial comparability with her own under the statutory standards.22
4. The motions for directed verdicts were not merely general but were addressed specifically to each count of the complaint. *445The motion as to the claims against S & S on counts I and II should not have been allowed. The evidence and permissible inferences (within the range of reasonable probability and not based on “mere speculation and conjecture,” see Poirier v. Plymouth, 374 Mass. 206, 212 [1978]) did not establish Rad-vilas’s claims against the individual defendants upon count III. Radvilas’s motions for a new trial presented no issues not already sufficiently discussed. The issues raised thereby are dealt with in effect by this opinion. The portion of the judgment entered on counts I and II for S & S is reversed. The balance of the judgment, for S & S on count III and for the individual defendants on all counts, is affirmed.
So ordered.