Mack v. Kijakazi

CourtDistrict Court, District of Columbia
DecidedFebruary 24, 2026
DocketCivil Action No. 2022-2807
StatusPublished

This text of Mack v. Kijakazi (Mack v. Kijakazi) is published on Counsel Stack Legal Research, covering District Court, District of Columbia primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Mack v. Kijakazi, (D.D.C. 2026).

Opinion

UNITED STATES DISTRICT COURT FOR THE DISTRICT OF COLUMBIA

TIFFANY M. o/b/o M.M., 1

Plaintiff,

v. Case No. 1:22-cv-2807-MJS

FRANK BISIGNANO, Commissioner of Social Security, 2

Defendant.

MEMORANDUM OPINION

Plaintiff Tiffany M. (“Ms. M”) challenges the Social Security Administration’s (“SSA”)

denial of an application for supplemental security income (“SSI”) benefits for her minor child,

MM. She argues that the Administrative Law Judge (“ALJ”) wrongly found that MM did not

satisfy the SSA’s functional-equivalence standards for disability and says the ALJ’s findings were

not supported by substantial evidence. On review, the Court concludes that the ALJ did not

adequately explain how they weighed the applicable evidence surrounding two of the functional-

equivalence factors and neglected to discuss at least some aspects of the relevant evidence

altogether. Accordingly, the Court GRANTS Ms. M’s motion for judgment of reversal (ECF No.

24), DENIES the Commissioner’s motion for judgment of affirmance (ECF No. 26), and

REMANDS this case to the Commissioner for further proceedings consistent with this opinion.

1 The names of Plaintiff and her child have been partially redacted in keeping with the recommendation of the Committee on Court Administration and Case Management of the Judicial Conference of the United States. See Memorandum, Privacy Concern Regarding Social Security and Immigration Opinions 3 (May 1, 2018), https://www.uscourts.gov/sites/default/files/18-ap-c-suggestion_cacm_0.pdf (recommending the use of “only the first name and last initial” in Social Security cases). 2 The current Commissioner is automatically substituted as the named defendant. Fed. R. Civ. P. 25(d).

1 BACKGROUND

I. Factual Overview

MM is a minor child diagnosed with asthma, selective mutism, speech delay, attention

deficit hyperactivity disorder (“ADHD”), and specific learning disabilities in reading, math, and

written expression. (ECF No. 14, Administrative Record (“AR”) at 381–86.) 3 Over the years, MM

has received a variety of medical treatments and interventions to treat her asthma and its related

symptoms. In addition, MM took part in a range of developmental evaluations, including with

District of Columbia Public Schools (“DCPS”), and broadly speaking, those evaluations pointed

to certain developmental delays for MM. Relatedly, based on its assessments, DCPS has regularly

developed individualized education plans (“IEPs”) for MM that provide specialized school

instruction, assistive technology for communication, and other supports.

II. The ALJ Decision

To qualify for SSI benefits under the Act, a claimant under eighteen years of age must

demonstrate a “medically determinable physical or mental impairment, which results in marked

and severe functional limitations, and … which has lasted or can be expected to last for a

continuous period” of at least one year. 42 U.S.C. § 1382c(a)(3)(C)(i). Under the Act’s

implementing regulations, a three-step analytical framework governs that analysis. 20 C.F.R.

§ 416.924. The SSA considers whether: (1) the claimant has engaged in “substantial gainful

activity,” (2) the claimant has an impairment or combination of impairments that are “severe,” and

(3) the impairment or combination of impairments “meet, medically equal, or functionally equal”

a listed impairment. Id. § 416.924(b)–(d); see Sullivan v. Zebley, 493 U.S. 521, 525–26 (1990).

3 Page citations to the AR refer to the running pagination at the lower right margin. Page citations to the parties’ briefing, by contrast, refer to the ones assigned by the Court’s electronic filing system.

2 The ALJ employed this three-step framework here. (AR at 22–36.) At step one, the ALJ

noted that MM had not engaged in substantial gainful activity since the application date. (Id. at

23.) At step two, the ALJ found that MM had a multitude of “severe” impairments, including:

“attention deficit hyperactivity disorder (ADHD), cognitive development delay, selective mutism,

language delay, learning disability … seasonal allergies, eczema, asthma, rhinitis, sleep disordered

breathing, and atopic dermatitis.” (Id.) At step three, the ALJ concluded that MM did not have an

impairment or combination of impairments that met or medically equaled a listed impairment (id.

at 23–25), so the ALJ then proceeded to analyze whether MM’s impairments functionally equaled

a listed impairment (id. at 25–36). That latter half of the step-three analysis—the functional-

equivalence aspect—is where Ms. M focuses her arguments for reversal.

To determine if an impairment is “functionally equivalent” to a listed impairment, the SSA

evaluates whether the claimant’s limitations are “marked” or “extreme” across six functional

domains: “(i) acquiring and using information; (ii) attending and completing tasks; (iii) interacting

and relating with others; (iv) moving about and manipulating objects; (v) caring for yourself; and

(vi) health and physical well-being.” See 20 C.F.R. § 416.926a(b)(1) (cleaned up). To “functionally

equal” a listed impairment, a child must have “marked” limitations in at least two domains, or an

“extreme” limitation in at least one. Id. § 416.926a(a). A “marked” limitation—one that is “more

than moderate” but “less than extreme”—is a limitation that “interferes seriously” with a child’s

“ability to independently initiate, sustain, or complete activities.” Id. § 416.926a(e)(2)(i). From a

standardized-testing perspective, a “marked” limitation is “the equivalent of the functioning”

associated with “scores that are at least two, but less than three, standard deviations below the

mean.” Id. An “extreme” limitation is one that “interferes very seriously” with a child’s “ability to

independently initiate, sustain, or complete activities.” Id. § 416.926a(e)(3)(i). It is the rating

3 assigned “to the worst limitations,” though it “does not necessarily mean a total lack or loss of

ability to function.” Id. From a standardized-testing perspective, it is “the equivalent of the

functioning” associated with “scores that are at least three standard deviations below the mean.”

Id.

Here, in assessing the six functional areas relevant to the analysis, the ALJ concluded that

MM had “no limitation” in the domain of moving about and manipulating objects and “less than

marked” limitations in the other five domains. (See AR at 26.) The ALJ’s findings across four of

these domain areas—acquiring and using information, attending and completing tasks, interacting

and relating with others, and health and physical well-being—are at issue in this case. 4 The Court

summarizes the ALJ’s treatment of each of these domains in turn.

A. Acquiring and Using Information

As to MM’s ability to acquire and use information, the ALJ’s discussion began by

describing a range of evidence, including scores on various intelligence, developmental, and

achievement tests; MM’s school-related IEPs from 2017 to 2020; MM’s speech and psychological

assessments; and Ms. M’s testimony.

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