                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

JA’VONCE WARRE, on behalf of              
E.T. IV, a minor child,
                                                 No. 04-35778
                Plaintiff-Appellant,
                v.                                D.C. No.
                                                CV-03-01072-HO
COMMISSIONER OF THE SOCIAL
                                                     OPINION
SECURITY ADMINISTRATION,
              Defendant-Appellee.
                                          
         Appeal from the United States District Court
                  for the District of Oregon
         Michael R. Hogan, District Judge, Presiding

                Submitted November 14, 2005*
                       Portland, Oregon

                     Filed February 17, 2006

    Before: Warren J. Ferguson, Andrew J. Kleinfeld, and
             Susan P. Graber, Circuit Judges.

                   Opinion by Judge Graber;
                   Dissent by Judge Ferguson




  *This panel unanimously finds this case suitable for decision without
oral argument. Fed. R. App. P. 34(a)(2).

                                1763
              WARRE v. COMMISSIONER OF THE SSA           1765


                         COUNSEL

David B. Lowry, Portland, Oregon, for the plaintiff-appellant.
1766             WARRE v. COMMISSIONER OF THE SSA
Leisa A. Wolf, Assistant Regional Counsel, Social Security
Administration, Seattle, Washington, for the defendant-
appellee.


                               OPINION

GRABER, Circuit Judge:

   Plaintiff Ja’Vonce Warre appeals from the district court’s
affirmance of a decision to terminate the Supplemental Secur-
ity Income (“SSI”) benefits of her minor son. We hold that (1)
the Commissioner of Social Security permissibly interpreted
Listing 100.02A, which defines a growth impairment to be a
disability, to require a continuing reduction in a child’s
growth velocity, rather than a mere continuation of shorter
stature; and (2) substantial evidence supports the finding that
Plaintiff’s son had medically improved to the point where he
no longer met Listing 100.02A. Accordingly, we affirm the
decisions below.

            FACTS AND PROCEDURAL HISTORY

   The pertinent facts are, for the most part, undisputed. Plain-
tiff applied for SSI benefits in 1996 on behalf of her son E.T.
IV, who was then seven months old. See 20 C.F.R. § 416.924
(defining eligibility for a child’s SSI benefits). The child is
diagnosed with isovaleric acidemia, a rare metabolic disorder
that causes concentrations of protein in the blood and tissues.
Upon consideration of the 1996 application, an administrative
law judge (“ALJ”) found E.T. IV to be disabled because his
impairment met the criteria of Listings 100.02 and 110.07C,
20 C.F.R. pt. 404, subpt. P., app. 1.1 His head size was below
  1
   Listing 100.02 defines as a disability:
        Growth impairment, considered to be related to an additional
      specific medically determinable impairment, and one of the fol-
      lowing:
                WARRE v. COMMISSIONER OF THE SSA                       1767
the fifth percentile, his height was at the forty-fifth percentile,
and his social/emotional development was at a level that was
less than fifty percent of his chronological age. By the age of
seven months the child had been hospitalized approximately
14 times due to his condition.

   The Social Security Administration (“SSA”) conducted a
continuing disability review in 2001. See 20 C.F.R. § 416.989
(explaining that the agency must evaluate recipients of SSI
benefits from time to time to determine their continuing eligi-
bility for benefits). The SSA found that E.T. IV had experi-
enced “medical improvement” and that he was no longer
eligible for SSI benefits. See 20 C.F.R. § 416.994a (stating
that SSI benefits may be terminated if the recipient has medi-
cally improved and is not currently disabled).

  Plaintiff requested a hearing, which took place on October
15, 2002. See 20 C.F.R. § 416.1430 (providing for a hearing
before an ALJ). Plaintiff, the child’s father, and medical
expert Dr. Perry Grossman testified. The ALJ also considered
documentary evidence from the child’s treating physicians
and his school.

  At the time of the 2002 hearing, E.T. IV was seven years
old. According to the evidence, he slept excessively, experi-
enced periods of lethargy, urinated frequently, sometimes wet

       A. Fall of greater than 15 percentiles in height which is sus-
    tained; or
      B.   Fall to, or persistence of, height below the third percentile.
  Listing 110.07 defines as a disability:
      Multiple body dysfunction due to any confirmed hereditary,
    congenital, or acquired condition with one of the following:
      ....
      C. Growth impairment as described under the criteria in
    100.02A . . . [.]”
1768          WARRE v. COMMISSIONER OF THE SSA
his bed and, because of the medications that he was taking,
smelled fishy when he perspired. E.T. IV had not been hospi-
talized since 2000, although he was taken to the emergency
room once in 2002 due to lethargy. He missed 21 days of
school during the 2000-2001 academic year because of his ill-
ness.

   The child’s parents testified that he was very forgetful and
learned slowly, but his teachers reported that he functioned at
grade level, had a normal attention span, and showed contin-
ued growth in his academic and social skills. He was found
to socialize well and to be generally an active child with nor-
mal strength, coordination, and gait.

   In 1998, E.T. IV’s height was in the fiftieth percentile. In
1999 he dropped to the twenty-fifth percentile in stature. In
2000 and 2001, his height remained in the twenty-fifth per-
centile. Early in 2000, his weight was in the twenty-fifth per-
centile as well; by October of that year his weight had risen
to the fiftieth percentile. At the time of the hearing, his head
circumference also was near the fiftieth percentile.

   At the 2002 hearing, Dr. Grossman testified that E.T. IV
did not meet the criteria for Listing 100.02A because that
Listing requires a “sustained decrease in the growth velocity.”
For this child, “the change didn’t persist. What persisted was
his height at the new percentile.” In other words, for more
than two years E.T. IV’s height had remained stable at the
twenty-fifth percentile, rather than continuing to slow down.
Dr. Grossman testified that the child’s prognosis was good
and that “he’s gotten over the most difficult period in his life.”

   Due to his condition, E.T. IV had to follow a strict low-
protein diet and take medications daily. His medications
included carnitine, which cost $250 per month; glycine, which
cost $150 per month; and calcium carbonate and iron supple-
ments, which cost $16 per month. Without those medications,
E.T. IV is at high risk of brain damage or death. Even with
                WARRE v. COMMISSIONER OF THE SSA                   1769
proper treatment, he is at risk for developmental delay or
brain damage “in the event that he is affected by an acute epi-
sode of illness that results in extreme metabolic acidosis that
cannot be controlled.” At the time of the 2002 hearing, Plain-
tiff and the child’s father did not have health insurance apart
from the child’s eligibility for SSI benefits.

   The ALJ determined that E.T. IV had experienced medical
improvement. He found that E.T. IV’s impairment no longer
met or medically equaled Listing 100.02 because, “[a]lthough
the claimant has had a fall of greater than 15 percentiles in
height, the medical records document the claimant has been
growing along the 25th percentile since February 2000.”2
Next, the ALJ found that E.T. IV’s impairment was severe,
but not disabling; although the child was “a[t] risk for medical
decompensation and/or death without his medications, his
ability to function in an age appropriate manner is only mildly
impacted.” The ALJ also considered whether the impairment
was functionally equivalent to any listed impairment. He
found that E.T. IV was markedly limited in the domain of
health and physical well-being but, because he did not have
extreme limitations in any one domain of functioning or
marked limitations in any two domains of functioning, the
impairment was not functionally equivalent to any listed
impairment. See 20 C.F.R. § 416.926a (providing standard).
Accordingly, the ALJ concluded that E.T. IV was no longer
eligible for SSI benefits.

 Plaintiff appealed to the district court, which affirmed the
ALJ’s 2002 decision. Plaintiff now timely appeals to us.
  2
   Because the earlier finding that the child met Listing 110.07 depended
on his meeting the criteria in Listing 100.02A, the ALJ’s conclusion nec-
essarily meant that the child no longer met Listing 110.07, either. See
supra note 1.
1770           WARRE v. COMMISSIONER OF THE SSA
                 STANDARD OF REVIEW

   We review de novo a district court’s decision upholding the
denial of social security benefits. Moisa v. Barnhart, 367 F.3d
882, 885 (9th Cir. 2004). We must affirm the decision if it is
supported by substantial evidence, which is “more than a
mere scintilla but not necessarily a preponderance.” Connett
v. Barnhart, 340 F.3d 871, 873 (9th Cir. 2003).

                        DISCUSSION

A.     The Meaning of Listing 100.02A

   [1] The principal issue in this appeal is whether the district
court and the ALJ properly interpreted Listing 100.02A,
which requires a “[f]all of greater than 15 percentiles in
height which is sustained.” (Emphases added.) Plaintiff
argues that the italicized phrase plainly means that a person
must sustain a fall in height that is never recovered. By con-
trast, the Commissioner of Social Security argues that “sus-
tained” in this context means accompanied by a continuing
reduction in growth velocity — in other words, not merely
that the child remains shorter in stature, but that his growth
rate has slowed.

   [2] In our view, Listing 100.02A is ambiguous. It is unclear
whether the “fall” (reduction in percentiles) must be “sus-
tained,” as the Commissioner argues, or whether only the
reduced “height” must be “sustained,” as Plaintiff contends.
The text of the Listing reasonably supports the meanings
urged by both parties.

   [3] In that circumstance, the Commissioner’s plausible
interpretation of her agency’s own regulation is entitled to
deference. Holohan v. Massanari, 246 F.3d 1195, 1202 n.1
(9th Cir. 2001). Here, the Commissioner’s interpretation is
consistent with the wording of the regulation and the govern-
ing statute; indeed, it is the more sensible reading in terms of
                WARRE v. COMMISSIONER OF THE SSA                    1771
what the Listing is trying to describe — a child who is not just
short in stature, but whose growth pattern is so abnormal that
he should be defined as disabled. Were we to adopt Plaintiff’s
interpretation, many a nondisabled child who simply ends a
growth spurt would be defined as disabled.

   [4] The Commissioner’s interpretation also is more consis-
tent with the Listing’s context. Listing 100.02B defines a
growth impairment involving a “[f]all to, or persistence of,
height below the third percentile.” Listing 100.02A omits
“persistence of” height more than 15 percentiles below a
child’s previous height; yet this is the reading that Plaintiff
would have us adopt. See SEC v. McCarthy, 322 F.3d 650,
656 (9th Cir. 2003) (“It is a well-established canon of statu-
tory interpretation that the use of different words or terms
within a statute demonstrates that [the drafter] intended to
convey a different meaning for those words.”).

  Finally, in support of the ALJ’s and the district court’s
holdings, the Commissioner relies on the Program Operations
Manual System (“POMS”), an internal SSA document.
POMS section DI 24598.020 states that “a child whose
growth delay satisfies the criteria specified in Listings
100.02A or 100.03 but whose fall in growth is not also
accompanied by a continuing reduction in growth velocity,
does not meet the severity level of those listings.”3 The POMS
  3
    We reject Plaintiff’s argument that, by citing the POMS, the Commis-
sioner is supplying a post-hoc rationalization for the ALJ’s decision.
Although the ALJ did not cite the POMS, the medical expert who testified
at the hearing did, and the ALJ clearly credited the expert’s and the Com-
missioner’s interpretation of the Listing. The Commissioner is not asking
this court to invent a new ground of decision; rather, the POMS simply is
additional support for the Commissioner’s and the ALJ’s position.
   We also reject Plaintiff’s argument that this POMS section adds a sub-
stantive requirement to Listing 100.02 and is therefore invalid. Although
policies authorized by the POMS that go beyond the SSA’s governing
statute and regulations may not be valid, see Briggs v. Sullivan, 886 F.2d
1132, 1144 (9th Cir. 1989), that is not the case here. The POMS merely
interprets the Listing in question.
1772           WARRE v. COMMISSIONER OF THE SSA
does not have the force of law, but it is persuasive authority.
Hermes v. Sec’y of Health & Human Servs., 926 F.2d 789,
791 n.1 (9th Cir. 1991).

   [5] For all these reasons, we hold that the district court and
the ALJ did not err in holding that Listing 100.02A requires
a continuing reduction in growth velocity.

B.     Substantial Evidence of Medical Improvement

   [6] Next, we consider whether substantial evidence sup-
ports the finding of the ALJ and the district court that E.T. IV
no longer met Listing 100.02A.4 We hold that substantial evi-
dence supports that conclusion, even though the child still suf-
fers from the same metabolic disorder that previously
rendered him disabled. It is undisputed that, at the time of the
2002 hearing, the child had steadily maintained growth at the
twenty-fifth percentile for more than two years. In addition,
the child’s head size, intellectual development, academic
functioning, socialization, attention span, strength, coordina-
tion, and gait had come within a normal range.

     [7] “Medical improvement” is defined as

      any decrease in the medical severity of [the claim-
      ant’s] impairment(s) which was present at the time
      of the most recent favorable medical decision that
      [the claimant was] disabled or continued to be dis-
      abled. . . . A determination that there has been a
      decrease in medical severity must be based on
      changes (improvement) in the symptoms, signs, or
      laboratory findings associated with [claimant’s]
      impairment(s).
  4
   It is undisputed that E.T. IV does not meet the criteria of Listing
100.02B.
              WARRE v. COMMISSIONER OF THE SSA              1773
20 C.F.R. § 416.994a(c). In other words, the key question is
not whether the claimant still suffered from the same medical
problem he had when benefits were awarded, but whether the
severity of the problem had decreased sufficiently to enable
him to engage in gainful activity. In short, E.T. IV’s continu-
ing diagnosis of isovaleric acidemia did not preclude a finding
of medical improvement.

   [8] Neither did the difficult economic circumstance of the
child’s family preclude a finding that he was no longer dis-
abled. Impairments that can be controlled effectively with
medication are not disabling for the purpose of determining
eligibility for SSI benefits. See, e.g., Brown v. Barnhart, 390
F.3d 535, 540 (8th Cir. 2004); Lovelace v. Bowen, 813 F.2d
55, 59 (5th Cir. 1987); see also Odle v. Heckler, 707 F.2d
439, 440 (9th Cir. 1983) (affirming a denial of benefits and
noting that the claimant’s impairments were responsive to
medication). It is true that benefits may not be denied to a dis-
abled claimant because of a failure to obtain treatment that the
claimant cannot afford. See, e.g., Gamble v. Chater, 68 F.3d
319, 321 (9th Cir. 1995). This rule implements the agency’s
official policy: Social Security Ruling (“SSR”) 82-59 pro-
vides that an individual’s failure to follow prescribed treat-
ment is justifiable if the individual is unable to afford such
treatment. See id. (noting that SSR 82-59 interprets 20 C.F.R.
§§ 404.1530 and 416.930 and is binding on the SSA). But
there is no statutory, regulatory, or judicial authority to sup-
port the rule that the dissent urges us to adopt, namely, that
disability benefits may not be discontinued if the claimant
cannot afford treatment without them. To the contrary, in the
only reported case in which this rule was proposed, the Fifth
Circuit flatly rejected it. Burnside v. Bowen, 845 F.2d 587,
592 (5th Cir. 1988), abrogated on other grounds by Sullivan
v. Zebley, 493 U.S. 521, 527 n.5 (1990).

   It may be that the dissent’s rule would comport best with
the Social Security Act’s overall purpose. See dissent at 1777.
On the other hand, holding that a claimant is entitled to con-
1774           WARRE v. COMMISSIONER OF THE SSA
tinue receiving SSI benefits when the claimant’s impairment
is not presently disabling, but when the claimant instead seeks
SSI benefits as a means of affording medication to prevent his
impairment from becoming disabling at an unknown time in
the future, could “open the door to virtually unlimited claims
for preventative benefits.” Burnside, 845 F.2d at 592. Decid-
ing between these competing policies is a choice for Congress
and the SSA in the first instance.

   Finally, neither the ALJ nor the district court made a fac-
tual finding that the family does not have, or cannot find,
resources for obtaining medications for E.T. IV. See SSR 82-
59 (requiring all possible community resources to be explored
and claimant’s financial circumstances to be documented).
Plaintiff may be eligible for other forms of assistance that will
allow her to continue to purchase her son’s expensive medica-
tions. See, e.g., Or. Rev. Stat. § 414.706(3) (funding health
services for persons under age 19 with incomes no more than
200 percent of federal poverty guidelines). Plaintiff does not
ask this court for a remand for factual findings. Thus, the
question whether the family can afford E.T. IV’s medications
and, if not, whether their financial condition entitles him to
continuing benefits, is not squarely presented.

C.     Functional Equivalence to a Listed Impairment

   Plaintiff also argues that the Commissioner erred in finding
that E.T. IV’s condition is not functionally equivalent to a
listed impairment. 20 C.F.R. § 416.926a. Although Plaintiff
made that argument to the Commissioner, she did not raise it
before the district court. Accordingly, this issue is waived,
Edlund v. Massanari, 253 F.3d 1152, 1158 n.7 (9th Cir.
2001), and we do not consider it.

     AFFIRMED.
              WARRE v. COMMISSIONER OF THE SSA               1775
FERGUSON, Circuit Judge, dissenting:

   Without his costly medication and special vegetarian diet,
E.T. IV will suffer progressive brain damage and other com-
plications of his inherited disease, isovaleric acidemia, that
will lead to his death. The majority would discontinue E.T.
IV’s SSI benefits without considering whether his mother, the
Plaintiff, can independently afford his life-saving medication.

   The Plaintiff contends, and there are no facts in the record
to refute her claim, that she cannot afford her son’s treatment
without the assistance of his SSI benefits. For nearly six
years, the Plaintiff received SSI benefits on behalf of E.T. IV
because her income was consistently below the level neces-
sary to qualify her for government assistance. See 20 C.F.R.
§ 416.202 (to qualify for SSI benefits, claimant must not have
more income or resources than are permitted). At the time of
the administrative hearing, neither the Plaintiff nor E.T. IV’s
father had health insurance that would cover E.T. IV. While
the majority suggests that the Plaintiff will be able to secure
state assistance to pay for her son’s treatment, maj. op. at
1773-74, the Plaintiff contends that under-funding of the Ore-
gon state health plan will leave her son without the treatment
he needs. Based on the Plaintiff’s established income qualifi-
cation for SSI, and the lack of facts refuting that qualification,
we can only conclude that the Plaintiff cannot independently
afford her son’s expensive medication and diet. Therefore, to
deny E.T. IV his SSI benefits is to deny him his life-saving
treatment.

  I cannot condone permitting a nine-year old boy to suffer
brain damage and death. For this reason, I dissent.

                             *****

   The law of this Circuit does not compel the majority’s con-
clusion that this Court should uphold the discontinuance of
E.T. IV’s SSI benefits. Indeed, firmly-established precedent
1776          WARRE v. COMMISSIONER OF THE SSA
requires the SSA to take a claimant’s ability to afford neces-
sary treatment into account when making an initial determina-
tion regarding whether the claimant is disabled, and therefore
entitled to SSI benefits. See, e.g., Gamble v. Chater, 68 F.3d
319, 321 (9th Cir. 1995). This principle can and should be
extended to ALJ decisions made in the context of continuing
disability reviews.

    In reaching its conclusion, the majority relies on the propo-
sition that “[i]mpairments that can be controlled effectively
with medication are not disabling for the purpose of eligibility
for SSI benefits.” Maj. op. at 1773. This statement is only par-
tially correct. Impairments that can be controlled effectively
with medication are not disabling for the purpose of SSI eligi-
bility if the claimant can obtain the medication, but chooses
not to without good reason. See Brown v. Barnhart, 390 F.3d
535, 540 (8th Cir. 2004) (“Failure to follow a prescribed
course of remedial treatment without good reason is grounds
for denying an application for benefits.” (internal quotation
marks omitted)). Claimants who cannot afford necessary med-
ication or treatment, however, cannot be denied benefits on
the basis that they have not undergone such treatment. See,
e.g., Gamble, 68 F.3d at 321 (holding that “[d]isability bene-
fits may not be denied because of the claimant’s failure to
obtain treatment he cannot obtain for lack of funds”); Brown,
390 F.3d at 540 (recognizing that “ ‘a lack of sufficient finan-
cial resources to follow prescribed treatment to remedy a dis-
abling impairment may be . . . an independent basis for
finding justifiable cause for noncompliance [with prescribed
treatment]’ ” (quoting Tome v. Schweiker, 724 F.2d 711, 714
(8th Cir, 1984))); Lovelace v. Bowen, 813 F.2d 55, 59 (5th
Cir. 1987) (holding that if “the claimant cannot afford the pre-
scribed treatment or medicine, and can find no way to obtain
it, the condition that is disabling in fact continues to be dis-
abling in law.” (internal quotation marks and citation omit-
ted)). Indeed, “[m]edicine or treatment an indigent person
cannot afford is no more a cure for his condition than if it had
never been discovered.” Lovelace, 813 F.2d at 59.
              WARRE v. COMMISSIONER OF THE SSA             1777
   This well-settled exception exists because the primary pur-
pose of the Social Security Act is “to give financial assistance
to disabled persons because they are without the ability to sus-
tain themselves.” Gamble, 68 F.3d at 322. To deny benefits
to a person because his disability could be prevented by medi-
cation that he cannot afford “directly contravene[s]” this pur-
pose. Id. Furthermore, “disabled children who live in low-
income households are certainly among the most disadvan-
taged of all Americans and . . . are deserving of special assis-
tance in order to help them become self-supporting members
of our society.” H.R. Rep. No. 92-231, at 147-48 (1971), as
reprinted in 1972 U.S.C.C.A.N. 4989, 5133-34.

   The case law that requires a claimant’s financial situation
to be taken into account in an initial SSI disability determina-
tion also counsels that such financial considerations be fac-
tored into continuing disability reviews in order to fulfill the
purposes of the Social Security Act.

   The majority justifies its decision to disregard E.T. IV’s
financial situation, and thereby deny him benefits, by citing a
Fifth Circuit case for the proposition that granting benefits to
a claimant “when the claimant’s impairment is not presently
disabling, but when the claimant instead seeks SSI benefits as
a means of affording medication to prevent his impairment
from becoming disabling at an unknown time in the future,
could ‘open the door to virtually unlimited claims for preven-
tative benefits.’ ” Maj. op. at 1774 (quoting Burnside v.
Bowen, 845 F.2d 587, 592 (5th Cir. 1988), abrogated on other
grounds by Sullivan v. Zebley, 493 U.S. 521, 527 n.5 (1990)).
But Burnside’s basic assumption regarding future “unlimited
claims” is flawed.

   The Plaintiff is not only seeking benefits to prevent her
son’s disability, she is seeking them to prevent his death. If
the Plaintiff cannot afford her son’s medication and special
diet, then it is not only “conceivable,” Burnside, 845 F.2d at
592, but certain that E.T. IV’s condition will deteriorate,
1778          WARRE v. COMMISSIONER OF THE SSA
resulting in his death if treatment is not resumed. Both Dr.
Koeller, an associate professor of pediatrics, and Dr. Gross-
man, the testifying medical expert, agree that, if untreated, a
child with isovaleric acidemia “suffers irreversible and pro-
gressive brain damage as well as seizures, acidosis, hyperam-
monemia,       pancytopenia      and/or     thrombocytopenia,
encephalopathy, hypocalcemia, and death.” No evidence in
the record refutes this dire conclusion.

   Therefore, a holding in favor of the Plaintiff would estab-
lish a rule that a child with a chronic illness, who was previ-
ously approved for SSI benefits, and whose condition
improved because of treatment paid for by those benefits, can-
not be denied continuing benefits because of that improve-
ment if denial of benefits would result in cessation of
treatment and put the child at high risk of brain damage and
death. This is not a rule that will give rise to “unlimited
claims for preventative benefits.” Maj. op. at 1774 (citation
omitted). To the contrary, it will fulfill the purpose of SSI by
helping a child from a low-income household survive a life-
threatening illness.

   To prevent E.T. IV from suffering brain damage and death,
we should reverse the District Court’s decision and remand
for reinstatement of E.T. IV’s SSI benefits.
