                        Docket No. 100183.

                       IN THE
                  SUPREME COURT
                         OF
                THE STATE OF ILLINOIS



CASSENS TRANSPORT COMPANY, Appellant, v. THE
                INDUSTRIAL COMMISSION et al. (Edwin
Ade, Appellee).

                 Opinion filed February 17, 2006.



    JUSTICE GARMAN delivered the judgment of the court, with
opinion.
    Chief Justice Thomas and Justices Freeman, McMorrow,
Fitzgerald, and Kilbride concurred in the judgment and opinion.
    Justice Karmeier took no part in the decision.



                             OPINION

    The Industrial Commission made an award to an injured worker,
Edwin Ade, in 1993. The award required Ade=s former employer,
Cassens Transport Company, to pay Ade a weekly wage differential
on a continuing basis. Ten years later, Cassens sought to terminate
that award on the grounds that Ade=s wage in the year 2002 matched
the wage he had been earning at the time of his injury in 1988. The
Commission denied this relief. The circuit court of Coles County
confirmed the Commission. The appellate court vacated this decision,
finding that the Commission lacked jurisdiction to review Ade=s
award. 354 Ill. App. 3d 807. We granted Cassens= petition for leave to
appeal. 177 Ill. 2d R. 315.
                            BACKGROUND
    On August 24, 1988, employee Edwin Ade injured his left hand
while working for employer Cassens Transport Company. As
compensation for this injury, the Illinois Industrial Commission 1
awarded Ade wage differential benefits in the amount of $203.55 per
week. Although evidence of the initial proceeding is absent from the
record in this appeal, the parties= briefing indicates that the
Commission made its award pursuant to section 8(d)(1) of the
Workers= Compensation Act (820 ILCS 305/8(d)(1) (West 2002)).
This section provides that an employee who is partially incapacitated
from pursuing his usual and customary line of employment shall
receive a portion of the difference between his former wages and the
wages he earns or is able to earn in his new employment. 820 ILCS
305/8(d)(1) (West 2002). An employee receiving an installment
award under section 8(d)(1) is entitled to compensation Afor the
duration of his disability.@ 820 ILCS 305/8(d)(1) (West 2002).
    A decade after Ade=s injury, Cassens renewed its interest in Ade=s
case. In the years 1999 and 2000, Cassens requested Ade=s income
tax returns. Ade declined to disclose this information. Cassens then
filed a motion with the Commission, requesting that it suspend Ade=s
benefits based on his refusal to provide current wage information.
The Commission denied this motion. While Cassens= appeal to the
circuit court was pending, the company served a subpoena on Ade=s
current employer and obtained 11 years of information about Ade=s
wages. The wage information revealed that in the year 2002, 14 years
after he was injured as a Cassens employee, Ade began to earn a
wage that exceeded the wage Cassens paid him at the time of his
injury.
    Cassens terminated the appeal of its original motion to suspend
Ade=s benefits. It filed a new motion to suspend benefits, arguing that
the wage discrepancy which gave rise to Ade=s award under section
8(d)(1) no longer existed. The Commission again denied Cassens=
motion. The Commission relied on an appellate court case, Petrie v.

   1
   The Industrial Commission is now known as the Illinois Workers=
Compensation Commission. 820 ILCS 305/13 (West 2004).




                                 -2-
Industrial Comm=n, 160 Ill. App. 3d 165 (1987), to determine that the
section 8(d)(1) phrase Afor the duration of his disability@ refers to the
duration of the employee=s physical or mental disability, not the
duration of an economic loss. Thus, the alleged change in Ade=s
earnings was irrelevant.
    The circuit court of Coles County denied Cassens= motion to
overturn the decision of the Commission, echoing the Commission=s
rationale. On appeal, the appellate court vacated the decision of the
Commission and dismissed Cassens= motion to suspend benefits,
finding that the Act did not give the Commission or the court
jurisdiction to entertain the motion. 354 Ill. App. 3d at 811. The
appellate court relied on section 19(h) of the Act, which requires
requests for review based on a change in disability to be filed within
30 months of the date of an award. 354 Ill. App. 3d at 810, citing 820
ILCS 305/19(h) (West 2002). The court determined that the
Aduration@ language in section 8(d)(1) of the Act did not give the
Commission jurisdiction to reopen or modify an award after the 30-
month period of section 19(h). 354 Ill. App. 3d at 811.
    However, before dismissing the appeal, the court addressed
Cassens= argument that the definition of Adisability@ in section 8(d)(1)
includes economic loss. The court noted that while Petrie addressed
the definition of Adisability@ in section 19(h) of the Act (820 ILCS
305/19(h) (West 2002)), it did so by examining the use of language
throughout the Act. 354 Ill. App. 3d at 809. The Petrie court
determined that Adisability@ means Aphysical disability@ because the
Act consistently uses other terms when referring to economic status.
354 Ill. App. 3d at 809, citing Petrie, 160 Ill. App. 3d at 171-72.
Thus, the section 8(d)(1) language addressing the duration of a
disability refers to the duration of a physical disability. 354 Ill. App.
3d at 809. In a special concurrence, one justice noted that this
discussion of the merits was dictum. 354 Ill. App. 3d at 811
(Holdridge, J., specially concurring). The special concurrence also
noted that the court=s holding on jurisdiction did not prevent an
employer from unilaterally terminating benefits based on a belief that
the duration of a claimant=s disability had ended. 354 Ill. App. 3d at
311 (Holdridge, J., specially concurring).
    The appellate court denied Cassens= petition for rehearing, but
filed a statement that the case involves a substantial question


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warranting consideration by this court. We granted Cassens= petition
for leave to appeal. 177 Ill. 2d R. 315.
                              ANALYSIS
    This case requires us to interpret section 8(d)(1) of the Workers=
Compensation Act (820 ILCS 305/8(d)(1) (West 2000)). This is a
matter of statutory construction, presenting a question of law that we
review de novo. R.D. Masonry, Inc. v. Industrial Comm=n, 215 Ill. 2d
397, 402 (2005). In interpreting the Act, our primary goal is to
ascertain and give effect to the intent of the legislature. Sylvester v.
Industrial Comm=n, 197 Ill. 2d 225, 232 (2001). We determine this
intent by reading the statute as a whole and considering all the
relevant parts. Sylvester, 197 Ill. 2d at 232; Flynn v. Industrial
Comm=n, 211 Ill. 2d 546, 555 (2004) (declining to read section
8(d)(1) in isolation). We must construe the statute so that each word,
clause, and sentence is given a reasonable meaning and not rendered
superfluous, avoiding an interpretation that would render any portion
of the statute meaningless or void. Sylvester, 197 Ill. 2d at 232. We
interpret the Act liberally to effectuate its main purpose: providing
financial protection for injured workers. Flynn, 211 Ill. 2d at 556.
    This appeal presents the threshold question of whether the
Workers= Compensation Commission has jurisdiction to reopen or
modify a 10-year-old wage differential award. Cassens argues that
section 8(d)(1) grants extended jurisdiction by allowing an employee
to receive compensation Afor the duration of his disability.@ 820 ILCS
305/8(d)(1) (West 2002). Cassens argues that the use of this phrase
suggests that the Commission may modify an award whenever a
disability no longer exists.
    In determining whether section 8(d)(1) of the Act allows limitless
modifications to an installment award for partial disability, we are
mindful that the Workers= Compensation Commission is an
administrative agency, lacking general or common law powers.
Alvarado v. Industrial Comm=n, 216 Ill. 2d 547, 553 (2005), citing
City of Chicago v. Fair Employment Practices Comm=n, 65 Ill. 2d
108, 113 (1976). Because its powers are limited to those granted by
the legislature, any action taken by the Commission must be
specifically authorized by statute. Alvarado, 216 Ill. 2d at 553, citing
Business & Professional People for the Public Interest v. Illinois
Commerce Comm=n, 136 Ill. 2d 192, 243 (1989). An act that is


                                  -4-
unauthorized is beyond the scope of the agency=s jurisdiction.
Alvarado, 216 Ill. 2d at 553-54, citing Business & Professional
People, 136 Ill. 2d at 243.
    Section 18 of the Act authorizes the Commission to settle all
questions arising under the Act (820 ILCS 305/18 (West 2002)), and
section 19 establishes the procedure by which the Commission is
authorized to do so (820 ILCS 305/19 (West 2002)). Section 19(f) of
the Act provides that a decision of the Commission is conclusive
unless a proceeding for review is commenced within 20 days of
receipt of notice of the decision. 820 ILCS 305/19(f) (West 2002).
Thus, the Commission may modify a conclusive decision only where
the Act specifically authorizes it to do so.
    This court recently noted that the Act specifies only two instances
where the Commission may modify a final award. Alvarado, 216 Ill.
2d at 555. Section 19(f) gives the Commission limited authority to
correct clerical errors. 820 ILCS 305/19(f) (West 2002); Alvarado,
216 Ill. 2d at 555. Section 19(h) gives the Commission authority to
review an installment award within 30 months of its entry when a
party alleges that the employee=s disability has recurred, increased,
diminished, or ended. 820 ILCS 305/19(h) (West 2002); Alvarado,
216 Ill. 2d at 555. Cassens argues that section 8(f) of the Act provides
a third route to modification of a final award, one which Cassens
analogizes to extended jurisdiction under section 8(d)(1).
    We note first that the plain language of section 8(d)(1), which
authorizes compensation to an injured worker Afor the duration of his
disability,@ does not mention modification of a final award. In
accordance with our responsibility to read the Act as a whole
(Sylvester, 197 Ill. 2d at 232; Flynn, 211 Ill. 2d at 555), we examine
each provision which does specifically authorize the Commission to
reopen a final award.
    Section 19(f) allows modifications to correct clerical errors:
              A(f) *** [T]he Arbitrator or the Commission may on his or
         its own motion, or on the motion of either party, correct any
         clerical error or errors in computation within 15 days after the
         date of receipt of any award by such Arbitrator or any
         decision on review of the Commission and shall have the
         power to recall the original award on arbitration or decision
         on review, and issue in lieu thereof such corrected award or

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       decision.@ 820 ILCS 305/19(f) (West 2002).
    Section 19(h) allows the Commission to reopen any installment
award for a limited time:
           A(h) ***
           *** [A]s to accidents occurring subsequent to July 1,
       1955, which are covered by any agreement or award under
       this Act providing for compensation in installments made as a
       result of such accident, such agreement or award may at any
       time within 30 months after such agreement or award be
       reviewed by the Commission at the request of either the
       employer or the employee on the ground that the disability of
       the employee has subsequently recurred, increased,
       diminished, or ended.@ 820 ILCS 305/19(h) (West 2002).
    Section 8(f) authorizes the reassessment of any award for total
and permanent disability:
           A(f) In case of complete disability, which renders the
       employee wholly and permanently incapable of work, or in
       the specific case of total and permanent disability as provided
       in subparagraph 18 of paragraph (e) of this Section,
       compensation shall be payable at the rate provided in
       subparagraph 2 of paragraph (b) of this Section for life.
           ***
           If any employee who receives an award under this
       paragraph afterwards returns to work or is able to do so, and
       earns or is able to earn as much as before the accident,
       payments under such award shall cease. If such employee
       returns to work, or is able to do so, and earns or is able to
       earn part but not as much as before the accident, such award
       shall be modified so as to conform to an award under
       paragraph (d) of this Section. If such award is terminated or
       reduced under the provisions of this paragraph, such
       employees have the right at any time within 30 months after
       the date of such termination or reduction to file petition with
       the Commission for the purpose of determining whether any
       disability exists as a result of the original accidental injury
       and the extent thereof.@ 820 ILCS 305/8(f) (West 2002).
    Each of these provisions includes language that is tailored to
authorize a review proceeding. Section 19(f) specifically gives the

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arbitrator and Commission the power to recall an award. Section
19(h) allows either party to petition for review of an installment
award within 30 months of its issuance. Section 8(f) indicates that
employers may cease payments when a totally and permanently
disabled employee returns to the workforce, giving the employee
authorization to petition the Commission for a review of the award.
The plain language of each section alerts employers and employees to
when review may be had and how to obtain it. In contrast, section
8(d)(1) contains no language about review proceedings:
            A(d) 1. If, after the accidental injury has been sustained,
        the employee as a result thereof becomes partially
        incapacitated from pursuing his usual and customary line of
        employment, he shall *** receive compensation for the
        duration of his disability *** equal to 66-b% of the
        difference between the average amount which he would be
        able to earn in the full performance of his duties in the
        occupation in which he was engaged at the time of the
        accident and the average amount which he is earning or is
        able to earn in some suitable employment or business after
        the accident.@ 820 ILCS 305/8(d)(1) (West 2002).
    The language of section 8(d)(1) does not authorize either party to
petition for review of an award, as section 19(h) does. It does not
authorize the Commission to recall an award, as section 19(f) does.
Nor does it authorize an employee to petition for review, as section
8(f) does. It would be inappropriate for us to read one of these
procedures into section 8(d)(1) when the legislature has included
none of them in that section. Reading the Act as a whole, we hold
that section 8(d)(1) does not specifically authorize the Commission to
reopen final installment awards for partial disability. Thus, the
Commission does not have jurisdiction under section 8(d)(1) to
reopen Ade=s final award. Our holding is based on the statutory
interpretation of section 8(d)(1) and does not affect the operation of
other sections of the Act.
    Cassens has asked the Commission to reopen an installment
award based on the allegation that Ade=s disability has diminished or
ended. Section 19(h) authorizes the Commission=s jurisdiction for this
purpose, but only for 30 months following the award=s issuance, a
time limit that Cassens has exceeded. 820 ILCS 305/19(h) (West


                                 -7-
2002); see also Cuneo Press, Inc. v. Industrial Comm=n, 51 Ill. 2d
548, 549-50 (1972) (declining to rely on public policy to enlarge
section 19(h) review period). Cassens also argues that section 8(f),
which allows totally and permanently disabled employees to petition
for review, implies that a review proceeding would also be
appropriate for partial disability under section 8(d)(1). However, the
presence of section 8(f)=s specific authorization actually defeats this
argument. The language of section 8(f), which gives the Commission
jurisdiction to determine whether a total and permanent disability
continues to exist, shows that the legislature could have similarly
authorized ongoing review of permanent partial disability if it had
intended to do so.
    Cassens argues that if the Commission does not have the ability to
modify an award under section 8(d)(1), then the section 8(d)(1)
statutory language authorizing an employee=s wage differential Afor
the duration of his disability@ is meaningless. Ade, in his brief, argues
that by making the award, the Commission determines that the
duration of the disability is permanent. Alternatively, he argues that
the duration clause gives an employer the option of terminating an
award once it unilaterally determines that the disability no longer
exists. At oral argument, counsel for Ade offered a third possible
interpretation of the duration clause, arguing that it gives the
Commission jurisdiction to modify an award upon an allegation that a
physical disability has ended, but not upon an allegation that the
recipient=s economic circumstances have changed.
    We reject the assertion that the duration clause of section 8(d)(1)
is meaningless if it does not grant jurisdiction to modify an award in
perpetuity. Rather, the duration clause is meaningful to the
Commission=s initial determination of the proper award in any section
8(d)(1) case. By its plain language, it allows arbitrators and the
Commission the option of determining that a claimant=s disability is
likely to end, abate, or increase after a certain duration, and awarding
compensation accordingly. See, e.g., Phillips v. Consolidated
Personnel Corp., Ill. Workers= Compensation Comm=n, No.
01WC 59242 (May 25, 2005) (awarding worker three separate
section 8(d)(1) wage differential awards for three separate durations).
    In the same way that trial judges and juries have one opportunity
to set an appropriate tort award for lost wages, arbitrators and the


                                  -8-
Commission must determine an appropriate wage differential in the
original workers= compensation proceeding, without authorization to
reexamine an award in perpetuity. As we have noted, permitting
employers to litigate ad infinitum does not comport with the Act=s
overriding purpose of early and thorough compensation for income
lost due to job-related injuries. Board of Education of the City of
Chicago v. Industrial Comm=n, 93 Ill. 2d 1, 14 (1982). Although
Cassens argues that this lack of jurisdiction is purely to the advantage
of the employee, we note that the Act similarly gives the Commission
no jurisdiction to reopen an installment award if an employee=s wages
should fall below the level contemplated in the initial award. See
Forest City Erectors v. Industrial Comm=n, 264 Ill. App. 3d 436, 441
(1994). Instead, the Act establishes that employees and employers
alike must use the opportunity of their initial hearing to present
evidence showing the likely duration of an injury and its effect on the
claimant=s earning capacity. See 820 ILCS 305/19 (West 2002)
(establishing procedure for resolving disputed questions of law and
fact).
    Cassens stated at oral argument that jurisdiction to reopen an
installment award under section 8(d)(1) would not be problematic
because the appropriateness of an installment award can be
continuously redetermined by a simple examination of the claimant=s
annual income tax return. However, this reflects an overly limited
view of the Commission=s role when making an initial award. To
receive an award under section 8(d)(1), an injured worker must prove
(1) that he or she is partially incapacitated from pursuing his or her
usual and customary line of employment and (2) that he or she has
suffered an impairment in the wages he or she earns or is able to earn.
820 ILCS 305/8(d)(1) (West 2002). This court has held that the
second prong of the inquiry properly focuses on earning capacity,
rather than the dollar amount of an employee=s take-home pay. Sroka
v. Industrial Comm=n, 412 Ill. 126, 128 (1952). In Franklin County
Coal Corp. v. Industrial Comm=n, 398 Ill. 528 (1947), the court
rejected the employer=s argument that a wage differential under
section 8(d) should be measured solely by gross yearly income.
Franklin, 398 Ill. at 532. Rather, the court looked to factors such as
wage increases, overtime, and increased hours of work. Although
Franklin and Sroka interpreted an earlier version of section 8(d), the
language Ais earning or is able to earn@ remains the same. Thus, the

                                  -9-
court=s conclusion that A[t]he test is the capacity to earn, not
necessarily the amount earned@ remains apt. Franklin, 398 Ill. at 533.
Although wages are indicative of earning capacity, they are not
necessarily dispositive. The initial hearing on an employee=s claim
gives both employers and employees the opportunity to present
evidence beyond wages to establish long-term earning capacity.
While this may result in an imperfect award, the legislature has not
currently authorized infinite opportunities for correction.
    This opportunity to prove earning capacity defeats Cassens=
arguments as to due process and the Aright to a remedy@ provision of
the Illinois Constitution. Cassens first argues that if section 8(d)(1)
does not confer jurisdiction for the Commission to modify an award,
it deprives the employer of its constitutional right to a remedy under
article I, section 12, of the Illinois Constitution (Ill. Const. 1970, art.
I, '12). Article I, section 12, states:
             AEvery person shall find a certain remedy in the laws for
         all injuries and wrongs which he receives to his person,
         privacy, property or reputation. He shall obtain justice by law,
         freely, completely, and promptly.@ Ill. Const. 1970, art. I, '12.
This court has noted that this provision is Amerely > Aan expression of
a philosophy and not a mandate that a >certain remedy= be provided in
any specific form.@ = @ Segers v. Industrial Comm=n, 191 Ill. 2d 421,
435 (2000), quoting DeLuna v. St. Elizabeth=s Hospital, 147 Ill. 2d
57, 72 (1992), quoting Sullivan v. Midlothian Park District, 51 Ill. 2d
274, 277 (1972). In this case, it is unclear what injury or wrong
Cassens has suffered. Cassens= continuing responsibility to pay Ade=s
wage differential is the remedy that Ade received as part of the
statutorily prescribed workers= compensation process; this
responsibility is not an injury suffered by Cassens. Even if Cassens
has suffered some sort of injury, the legislature has determined that
Cassens must seek any relief in the initial proceeding before the
Commission or within 30 months thereafter. 820 ILCS 305/8(d)(1),
12(h) (West 2002). Article I, section 12, does not create a right to the
specific review action that Cassens desires. See Segers, 191 Ill. 2d at
435.
    Cassens also argues, briefly, that without continuing jurisdiction
to reopen an award, section 8(d)(1) violates Cassens= right to due
process. In support of this argument, Cassens= brief states, AThe

                                  -10-
Appellant must *** be afforded the right to a hearing to determine
whether the disability exists. Otherwise, if there is no right for a
hearing, section 8(d)(1) should be found unconstitutional for granting
a limitation on the award, with no process to enforce it.@ As explained
above, the Commission may enforce the limitation found in the
duration clause when it makes its initial award. Cassens received a
hearing before Ade received an award of any kind. Cassens= right to
due process is not violated by the Commission=s absence of
jurisdiction for perpetual rehearings.

                           CONCLUSION
    For the reasons stated above, we hold that the Commission has no
jurisdiction to modify Ade=s award. This holding makes it
unnecessary to address Cassens= arguments as to the definition of
Adisability@ in section 8(d)(1) and, accordingly, the appellate court=s
discussion of that issue was improper. Nevertheless, we affirm the
appellate court=s dismissal of this appeal.

                                                             Affirmed.

   JUSTICE KARMEIER took no part in the consideration or
decision of this case.




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