concurring in part and dissenting in part. Contrary to our clearly defined law, the court today adopts an interpretation of the Workers’ Compensation Act (act) pertaining to the method of calculating cost-of-living adjustments (COLAs) urged upon us only by the Connecticut Business and Industry Association (CBIA) and the American Insurance Association (AIA), two of the parties filing amicus curiae briefs.1 That *696method of calculating COLAs for persons injured prior to October 1,1991, will result in totally disabled workers, dependent surviving spouses, and minor children of workers killed in the course of their employment, receiving less in weekly compensation benefits. Indeed, the decision of the majority today means that from October 1, 1991, many of those beneficiaries received amounts in excess of that to which they were entitled and they conceivably could be required to repay those amounts. The second injury fund of the state of Connecticut (fund), which is obligated to make these payments to the plaintiff, Karyn Gil, does not, before this court, take the position adopted by the majority. Instead, the fund argues, in the first instance, for an inteipretation that is more moderate, leaving the plaintiff and other beneficiaries entitled to COLAs prior to October 1, 1991, in the same position that they were in before the state unilaterally decided to reduce their awards.2
We are required in this appeal to answer the following: (1) whether the provisions of § 27 of No. 91-339 of the 1991 Public Acts (P.A. 91-339), which amended General Statutes (Rev. to 1991) § 31-307a (a), applies retroactively for COLA compensation involving injuries that occurred prior to October 1, 1991; and (2) if so, the method of calculating those COLAs.
I will briefly restate the undisputed facts in this case. The plaintiff, while in the employ of the defendant Courthouse One in 1983, was exposed to chlorine gas. As a result of this exposure, she suffered a permanent physical impairment to her respiratory system and has been totally disabled since February, 1984. On November 5, 1986, the fund assumed liability for the plaintiffs injuries.
The plaintiff was initially found to be entitled to weekly basic compensation benefits of $93.35 per week *697(base rate). The base rate was thereafter increased on October 1 of each subsequent year as a result of the COLAs she received pursuant to § 31-307a (a). The method of calculating the COLAs under § 31-307a (a) prior to October 1, 1991, was the flat grant accrual method — the annual COLA was based upon the difference between the maximum compensation in effect at the time of the adjustment and the maximum in the preceding October 1. The compensation was therefore the base rate plus the sum of each annual COLA (flat grant method). In this case, under the flat grant method, the plaintiff would receive as of October 1, 1995, her base rate of $93.35 plus the sum of the annual COLAs in the amount of $239,3 totaling $332.35.
The legislature adopted P.A. 91-339, thereby amending § 31-307a (a) by substituting a percentage adjustment for the flat grant. Public Act 91-339, § 27, provides in relevant part: “If the maximum weekly compensation rate as determined under the provisions of section 31-309 ... to be effective as of any October first following the date of the injuiy, is greater than the maximum weekly compensation rate prevailing as of the date of the injury, the weekly compensation rate which the injured employee was entitled to receive at the date of the injury shall be increased by the percentage of the increase in the maximum weekly compensation rate required by the provisions of section 31-309 . . . from the date of the injuiy to such October first. ...”
On October 30, 1991, commissioner John A. Arcudi, the former chairperson of the workers’ compensation commission (commission), administratively issued a clarifying memorandum concerning P.A. 91-339 (Arcudi memorandum). Implicitly recognizing the “date of *698injury rule” with respect to compensation — which will be discussed later in this opinion4 — he viewed COLAs as an “adjustment,” rather than “compensation.” Arcudi concluded that P.A. 91-339 applied to injuries prior to October 1, 1991, reasoning that “[i]n interpreting the law over the years, ‘compensation rate’ has come to mean the worker’s base rate computed at the time of injury.5 The cost-of-living increase has been called an ‘adjustment.’ Therefore, when section 27 changes the computation of the ‘adjustment’ to a percentage increase rather than a dollar amount and has no saving clause as does [P.A. 91-339] section 29 when it refers to the compensation rate, the legislative intent is to have all cost-of-living adjustments computed after October 1, 1991 to be done on a percentage basis.”
The Arcudi memorandum, interpreting P.A. 91-339, § 27, also determined that the COLAs should be calculated for persons injured prior to 1991 in the following manner. The base rate plus the accumulated COLAs as of September 30, 1991, is multiplied by the percentage increase from September 30, 1991, to the year in question; this COLA is then added to the base rate plus the accumulated COLAs as of September 30, 1991, in order to determine the compensation rate for the year (Arcudi method). Applying the Arcudi method, as the fund did until 1995, would result in the plaintiff receiving, as of October 1,1995, the base rate of $93.35 and accumulated COLAs as of September 30,1991, of $134, plus apercentage increase of 21.9 percent in the amount of $49.79, totaling $277.14. All payors, including the fund with respect to the plaintiff, followed the Arcudi method, with a slight variation, which amounted to an insignifi*699cant difference,6 for calculating COLAs for persons injured prior to October 1, 1991, until 1995.
On June 5,1995, in Wolfe v. JAB Enterprises, Inc., 14 Conn. Workers’ Comp. Rev. Op. 127 (1995), an opinion authored by Jesse M. Frankl, the chairperson of the commission, the workers’ compensation review board (review board) held that P.A. 91-339, § 27, required that the calculations be made as follows: the base rate multiplied by the percentage of increase between the maximum rate on the date of injury and the date of adjustment (Wolfe method). Id., 129-30. The fund, applying the Wolfe method, recalculated the plaintiffs compensation as of October 1,1995, which would result in the plaintiff receiving 169 percent of her base rate of $93.35, totaling $157.76. The plaintiff, contesting the redetermination of her weekly compensation, brought the matter before the commission for New Britain. The New Britain commission rejected Wolfe and ordered that the plaintiffs weekly compensation benefits be calculated under the Arcudi method.
The fund appealed from the New Britain commission’s order to the review board. After the appeal was taken, on February 9, 1996, Frankl administratively issued a memorandum, essentially reversing his position in Wolfe, which provided that for all persons injured prior to October 1, 1991, their COLAs should be calculated in accordance with the Arcudi method. On May 1,1996, the review board7 concluded that the provisions of P.A. 91-339, § 27, were not retroactive and ordered *700that the plaintiffs compensation be recalculated based upon the flat grant method, thereby substantially increasing the weekly amount that would be allowed under Wolfe or the Arcudi method. Subsequently, the fund brought this appeal.8
On appeal, the CBIA and AIA argue, and the majority agrees, that the COLAs for any given year should be calculated based upon the base rate, multiplied by the percentage increase in the maximum rate between 1991 and the year in question; that COLA is then added to the base rate plus the COLAs as of September 30, 1991, in order to determine the compensation rate for the year (CBIA/AIA method). Applying the CBIA/AIA method would result in the plaintiff receiving as of October 1, 1995, the base rate of $93.35 and the accumulated COLAs as of September 30,1991, of $134, plus apercentage increase of 21.9 percent of the base rate of $93.35 in the amount of $20.44, totaling $247.79.
In sum, the amounts the plaintiff would receive as of October 1, 1995, under each method are as follows:
Wolfe method $157.76
CBIA/AIA method $247.79
Arcudi method $277.14
Flat grant method $332.35
I
Although I agree with the majority that the provisions for calculating COLAs pursuant to P.A. 91-339, § 27, are *701retroactive, in my view, it is not as easy a call as the majority opinion would make it appear. Indeed, if we were writing on a clean slate and applied the plain language of P.A. 91-339,9 which was confirmed by the legislative debates,10 the “date of injury rule,”11 our gen*702eral rules of statutory construction,12 and our longstanding rule liberally construing workers’ compensation *703laws,13 I would be compelled to conclude that the review board was correct in holding that P.A. 91-339, § 27, has no retroactive application and those who were injured prior to October 1, 1991, are entitled to COLAs based upon the flat grant method.
I reach the same result as to retroactivity that the majority does, but I do so only because of the Arcudi *704memorandum. Arcudi, as the then chairperson of the commission, interpreted P.A. 91-339, § 27, as applying retroactively to those who were injured prior to October 1, 1991. “[T]he interpretation of a statute by an agency created to administer that statute is traditionally accorded great deference.” E.I.S., Inc. v. Board of Registration for Professional & Land Surveyors, 200 Conn. 145, 148, 509 A.2d 1056 (1986); see Crochiere v. Board of Education, 227 Conn. 333, 354, 630 A.2d 1027 (1993). “It is a familiar rule of statutory and constitutional construction that such usage, while not absolutely binding upon the courts, is entitled to great weight. Water Commissioners v. Curtis, 87 Conn. 506, 511, 89 Atl. 189 [1913] .... Where the law has contemporaneously been put into operation, and in doing so a construction has necessarily been put upon it, this construction, especially if followed for some considerable period, is entitled to great respect, as being very probably a true expression of the legislative purpose, and is not lightly to be overruled, although it is not conclusive. 2 Cooley, Taxation (4th Ed.) pp. 1111, 1112, § 502.” (Citations omitted; internal quotation marks omitted.) Savings Bank of Rockville v. Wilcox, 117 Conn. 188, 194-95, 167 A. 709 (1933). In this case, it is particularly appropriate to give deference to Arcudi’s interpretation that P.A. 91-339, § 27, has retroactive application for those injured before October 1, 1991, because during the four year period that P.A. 91-339, § 27, was applied, the commission, payors and beneficiaries did not challenge that determination. Id., 195.
Further, the legislature revisited COLAs on two separate occasions before the date of the review board decision in this case, and took no action to reverse the retroactive interpretation that the Arcudi memorandum placed on P.A. 91-339, § 27. In 1992, the legislature amended the COLA provisions of General Statutes § 31-306 (a) (2) in order to substitute the percentage method *705for the flat grant method, which was similarly adopted in P.A. 91-339, § 27, for compensation to dependents of deceased workers. See Public Acts 1992, No. 92-31, § 4. Subsequently, in 1993, the legislature revisited COLAs and eliminated them for injuries sustained on or after July 1, 1993. See Public Acts 1993, No. 93-228, § 15.
We have stated that there “is the inference of legislative concurrence with the agency’s interpretation to be drawn from legislative silence concerning that interpretation, especially where the legislature makes unrelated amendments in the same statute.” Connecticut Light & Power Co. v. Public Utilities Control Authority, 176 Conn. 191, 198, 405 A.2d 638 (1978). Indeed, it is clear from its action that the legislature was greatly concerned about the status of workers’ compensation and the escalating costs on business and industry during the intervening period. Because the Arcudi memorandum “affects so many of the state’s citizens, and because of the interest evidenced by the . . . General Assembly . . . we may not assume that the members of the General Assembly . . . were unaware of, or ignored” the Arcudi method. Id., 199.
“We, therefore, construe the legislative silence as legislative concurrence in that interpretation. That legislative concurrence is ‘presumptive evidence’ of the correctness of the administrative interpretation. 2A Sutherland, [Statutory Construction (4th Ed. Sands 1973) § 49.10], pp. 261-62. This ‘presumptive evidence’ of correctness we add to the persuasive effect normally given to an administrative interpretation. Coupled, these two considerations outweigh any arguments that might be advanced for a contrary interpretation.” Connecticut Light & Power Co. v. Public Utilities Control Authority, supra, 176 Conn. 199. Here, where the legislature twice revisited § 31-307a (a) and failed to take any action to reverse Arcudi’s interpretation, the legislature is presumed to have acquiesced in its retroactive *706application. Accordingly, on the basis of the above reasoning, I concur with the majority that P.A. 91-339, § 27, has retroactive application to those injured before October 1, 1991.
II
The same rules of statutory construction used to arrive at the conclusion that P.A. 91-339, § 27, applies retroactively to persons who were injured prior to October 1,1991, must be applied to determine the legislative intent with respect to the method to be used in order to calculate COLAs for those beneficiaries. The legislative silence with respect to the Arcudi method, which creates presumptive evidence of its correctness, coupled ■with the four years of consistent administrative interpretation, leads me to the inescapable conclusion that the legislature intended that COLAs be calculated for those beneficiaries in accordance with the Arcudi method. Connecticut Light & Power Co. v. Public Utilities Control Authority, supra, 176 Conn. 199.
The majority rejects the Arcudi method, however, because (1) there was a slight variation in calculating the COLAs under this method, and (2) the review board had issued an inconsistent interpretation. First, the fund itself, which advocates for the Arcudi method in this appeal, points out that the two interpretations in calculating the Arcudi method resulted in an insignificant variation in the amount of benefits. See footnote 6. Furthermore, it can be presumed that the legislature concurred in the Arcudi method, despite this interpretational variation, because the two times that the legislature revisited COLAs, first in 1992 and then in 1993, it neglected to tinker with the Arcudi method.
Second, subject to this insignificant variation, the industry calculated COLAs from October 1,1991, to the date of the decision in this case in accordance with the Arcudi method. It is correct, as the majority points out, *707that on June 5, 1995, the review board decided Wolfe, changing the COLA calculation. That decision, however, was short-lived. Frankl, the author of Wolfe, issued a memorandum dated February 9, 1996, to all commissioners and payors that COLAs calculated prior to October 1, 1991, were to be based on the Arcudi method. Therefore, the majority’s reliance on the aberrant Wolfe decision cannot be justified to overcome four years of adherence to the Arcudi method.
Furthermore, in adopting the method of calculation urged upon us only by the CBIA and the ALA, the majority fails to acknowledge our long-standing rule that the act should be liberally interpreted. “[W]e are mindful of the principles underlying Connecticut practice in workmen’s compensation cases: that the legislation is remedial in nature . . . and that it should be broadly construed to accomplish its humanitarian purpose.” (Citation omitted; internal quotation marks omitted.) Dubois v. General Dynamics Corp., 222 Conn. 62, 67, 607 A.2d 431 (1992). “Because the [act] is a remedial statute, this court should not impose limitations on the benefits provided for a disabled worker that the statute itself does not clearly specify.” Misenti v. International Silver Co., 215 Conn. 206, 210, 575 A.2d 690 (1990).
In my view, there is no basis for the CBIA/AIA method of calculating the COLAs for those who were injured before October 1, 1991, thus the calculation that would provide the plaintiff with weekly compensation of $247.79 should be rejected. Rather, the plaintiff’s COLAs should be calculated based on the Arcudi method, a method followed by all payors for a period of over four years, which would provide weekly compensation to the plaintiff in the amount of $277.14.
Accordingly, I concur that P.A. 91-339, § 27, applies retroactively to those who were injured prior to October 1, 1991, but disagree as to the method of calculating the COLAs for those beneficiaries.
The Connecticut Trial Lawyers Association was also granted permission to appear as amicus curiae and filed a brief.
See footnote 8.
The annual increases in maximum compensation were: 1984 — $36; 1985 — $16; 1986 — $11; 1987 — $21; 1988 — $18; 1989 — $15; 1990 — $17; 1991 — $12; 1992 — $22; 1993 — $16; 1994 — $38; and 1995 $17, totaling $239.
See footnote 11.
Arcudi, however, did not take into account Public Acts 1991, No. 91-32, § 1, adopted earlier in the legislative session, which amended General Statutes (Rev. to 1991) § 31-275, and defined “compensation” under the act to include “any actfustment in benefits or payments required by this” act. See General Statutes § 31-275 (4); see also footnote 9.
In subsequent years, some payors calculated COLAs by taking the claimant’s ongoing rate as of the then current September 30, and then adding the percentage change in the maximum rate from the previous October 1 to the current October 1. This variation, as the fund points out, resulted in a minimal difference in compensation.
The composition of the review board did not include Frankl, but consisted of commissioners Amado J. Vargas, Michael S. Miles and Robin L. Wilson.
Although the fund, represented by the attorney general, unilaterally reduced the plaintiffs compensation in accordance with the Wolfe method and appealed to the review board from the commissioner’s order to recalculate the compensation in accordance with the Arcudi method, the fund has reversed its position 180 degrees before this court. The fund now argues that the Arcudi method correctly implements P.A. 91-339, § 27. Indeed, the attorney general in his brief states that the Arcudi method “appropriately follows the Compensation Commission’s long-standing interpretation of § 31-307a, and results in the greatest fairness to the maximum number of claimants.”
“In construing any statute, we seek to ascertain and give effect to the apparent intent of the legislature. . . . It is an axiom of statutory construction that legislative intent is to be determined by an analysis of the language actually used in the legislation. . . . [Wjhen the language of a statute is plain and unambiguous, we need look no further than the words themselves because we assume that the language expresses the legislature’s intent.” (Citations omitted; internal quotation marks omitted.) Dos Santos v. F. D. Rich Construction Co., 233 Conn. 14, 20, 658 A.2d 83 (1995).
Section 50 of P.A. 91-339 clearly stated: “Nothing in this act shall be construed to affect any claims for compensation arising from, any injury that occurred before October 1, 1991. Nothing in this act shall be construed to reduce the amount of any compensation awarded for any injury that occurred before October 1,1991.” (Emphasis added.) Earlier in that session, the legislature defined compensation to include payments under the act and “any adjustment in benefits or payments required by this” act. Public Acts 1991, No. 91-32, § 1; see General Statutes § 31-275 (4). Nevertheless, I recognize that it is arguable that some of this language can be construed as ambiguous, in that P.A. 91-339, § 50, could be read to refer to the accumulated COLAs as of September 30, 1991.
“When the language of a statute is unclear, we may ascertain the intent of the legislature by looking beyond the language to the statute’s legislative history and the purpose that the statute was intended to serve.” Weinberg v. ARA Vending Co., 223 Conn. 336, 341, 612 A.2d 1203 (1992). The legislative debates with respect to P.A. 91-339 confirm that the legislature intended that the changes in compensation not be retroactive. See 34 H.R. Proc., Pt. 24, 1991 Sess., p. 9039, remarks of Representative Joseph Adamo (“[the amendments] would be prospective, everyone who [is] on the existing benefits would be grandfathered under those existing benefits”).
This court has held that “new workers’ compensation legislation affecting rights and obligations as between 1he parties, and not specifying otherwise, applie[s] only to those persons who received injuries after the legislation became effective, and not to those injured previously. This date of iqjury rule was first referred to in 1916, in Schmidt v. O.K. Baking Co., 90 Conn. 217, 220-21, 96 A. 963 (1916). In 1921, we stated that [t]he obligations of the employer to dependents of an employee in case of the death of an injured employee are . . . fixed and determined by the statute in force at the time of injury. . . . Quilty v. Connecticut Co., 96 Conn. 124, 127, 113 A. 149 (1921).
“In the fifty-seven years that followed we continued to use the date of ipjury rule in determining the rights and obligations as between the parties *702following revisions to the Workers’ Compensation Act. See Rossi v. Jackson Co., 120 Conn. 456, 460, 181 A. 539 (1935); Farmer v. Bieber-Goodman Corporation, 118 Conn. 299, 301, 172 A. 95 (1934); Panico v. Sperry Engineering Co., 113 Conn. 707, 709, 156 A. 802 (1931); Preveslin v. Derby & Ansonia Developing Co., 112 Conn. 129, 142, 151 A. 518 (1930). As recently as 1975, we acknowledged the continued existence of the rule although finding it inapplicable to changes in the appellate procedures which we concluded did not affect rights and obligations as between the parties. See Chieppo v. Robert E. McMichael, Inc., 169 Conn. 646, 649-50, 363 A.2d 1085 (1975).” (Emphasis in original; internal quotation marks omitted.) Iacomacci v. Trumbull, 209 Conn. 219, 222-23, 550 A.2d 640 (1988).
Indeed, the date of injury rule was codified in Public Acts 1993, No. 93-228, § 21, when the legislature amended § 31-309 (a) as follows: “[WJeekly compensation received by an injured employee whose injury occurred before July 1, 1993, shall be computed according to the provisions of the law in effect at the time of the injury.”
The majority acknowledges that General Statutes § 55-3, as it must, provides: “No provision of the general statutes, not previously contained in the statutes of the state, which imposes any new obligation on any person or corporation, shall be construed to have a retrospective effect.” The legislature can rebut this presumption that statutory changes affecting substantive rights are prospective only if the legislature clearly and unequivocally expresses an intent that the changes are retrospective. State v. Lizotte, 200 Conn. 734, 740-41, 517 A.2d 610 (1986). The majority, however, stands § 55-3 on its head by concluding that P.A. 91-339, § 27, expressly provides for retroactive application because it applies to all employees injured “on or after October 1, 1969.” That ignores the fact that the date of October 1, 1969, was in the original statute as the starting date for granting COLAs and only appears in P.A. 91-339, § 27, because the statute is duplicated in the amended form by indicating additions in capital letters and deletions in brackets. See State v. Kozlowski, 199 Conn. 667, 675, 509 A.2d 20 (1986) (“The legislature characteristically casts acts which alter language within existing statutory subsections in the form of repeal and substitution, reserving the label of amendment for acts which add entirely new subsections. This format complies with the requirements of [General Statutes] § 2-18 that an act altering a statutory subsection set out that subsection in its entirety, with changes clearly marked.”).
Public Act 91-339, § 27, provides: “Subsection (a) of section 31-307a of the general statutes, as amended by section 24 of public act 91-32, is repealed and the following is substituted in lieu thereof:
“(a) The weekly compensation rate of each employee entitled to receive compensation under section 31-307 as amended by section 23 of [this act] PUBLIC ACT 91-32 AND SECTION 26 OF THIS ACT, as a result of an injury sustained on or after October 1, 1969, which totally disables the employee continuously or intermittently for any period extending to the following *703October first or thereafter, shall be adjusted annually as provided in this subsection as of the following October first, and each subsequent October first, to provide the injured employee with a cost-of-living adjustment in his weekly compensation rate as determined as of the date of the injury under section 31-309, AS AMENDED BY SECTION 29 OF THIS ACT. If the maximum weekly compensation rate as determined under the provisions of section 31-309, AS AMENDED BY SECTION 29 OF THIS ACT, to be effective as of any October first following the date of the injury, is greater than the maximum weekly compensation rate prevailing as of the date of the injury, the weekly compensation rate which the injured employee was entitled to receive at the date of the injury shall be increased by the [dollar amount] PERCENTAGE of the increase in the maximum weekly compensation rate required by the provisions of section 31-309, AS AMENDED BY SECTION 29 OF THIS ACT, from the date of the injury to such October first. The cost-of-living increases provided under this subsection shall be paid by the employer without any order or award from the commissioner. The adjustments shall apply to each payment made in the next succeeding twelvemonth period commencing with the October first next succeeding the date of the injury.”
It is simply wrong to conclude that, because the starting date for COLAs was in the statute when it was originally enacted, the legislature intended the amendment to apply to iryuries that occurred back to October 1, 1969. This “reasoning” would then lead to the conclusion that the legislature intended all COLAs, dating back to October 1, 1969, to be calculated on a percentage basis. This result, however, is what the legislature specifically disavowed in enacting P.A. 91-339, § 50. Furthermore, General Statutes § 1-1 (u) provides: “The passage or repeal of an act shall not affect any action then pending.”
“[W]e are mindful of the principles underlying Connecticut practice in workmen’s compensation cases: that the legislation is remedial in nature . . . and that it should be broadly construed to accomplish its humanitarian purpose.” (Citation omitted; internal quotation marks omitted.) Dubois v. General Dynamics Corp., 222 Conn. 62, 67, 607 A.2d 431 (1992). “Because the Workers’ Compensation Act is a remedial statute, this court, should not impose limitations on the benefits provided for a disabled worker that the statute itself does not clearly specify.” Misenti v. International Silver Co., 215 Conn. 206, 210, 575 A.2d 690 (1990).