                                PUBLISHED

                  UNITED STATES COURT OF APPEALS
                      FOR THE FOURTH CIRCUIT


                               No. 14-2324


SEA “B” MINING    COMPANY,    c/o   HealthSmart   Casualty   Claims
Solutions,

                Petitioner,

           v.

SHIRLEY ADDISON, widow of Jerry Addison, deceased; DIRECTOR,
OFFICE OF WORKERS’ COMPENSATION PROGRAMS, UNITED STATES
DEPARTMENT OF LABOR,

                Respondents.



On Petition for Review of an Order of the Benefits Review Board.
(14-0019 BLA)


Argued:   December 9, 2015                    Decided:   July 29, 2016


Before NIEMEYER, DUNCAN, and AGEE, Circuit Judges.


Petition for review granted; order vacated and remanded by
published opinion. Judge Agee wrote the opinion, in which Judge
Niemeyer and Judge Duncan joined.


ARGUED: Timothy Ward Gresham, PENNSTUART, Abingdon, Virginia,
for Petitioner.    Victoria Susannah Herman, WOLFE WILLIAMS &
REYNOLDS, Norton, Virginia, for Respondent Shirley Addison. ON
BRIEF: Joseph E. Wolfe, WOLFE WILLIAMS & REYNOLDS, Norton,
Virginia, for Respondent Shirley Addison.
AGEE, Circuit Judge:

        Jerry Addison applied for financial assistance under the

Black        Lung    Benefits      Act,     30    U.S.C.      §§   901-944     (“the     Act”),

claiming that he suffered from coal-dust induced pneumoconiosis

as a result of his prior work as a coal miner.                            Over conflicting

medical evidence, an Administrative Law Judge (“ALJ”) found that

Addison was entitled to benefits under the Act because he had

established the existence of clinical and legal pneumoconiosis

that        resulted    in    a    total    respiratory         disability.         Addison’s

former employer, Sea B Mining Co. (“Sea-B”), filed a petition

for review, arguing the ALJ erred in several ways which were not

harmless.            For     the       reasons    described        below,     we   grant   the

petition for review, vacate the order awarding benefits, and

remand for further proceedings. 1



                                                 I.

        We     begin    with       a    brief    discussion        of   the   statutory    and

regulatory framework, which provides context for the events of

this        case.      The     Act       creates       an   adversarial       administrative

procedure           designed       to    determine          whether     miners     (or   their

surviving dependents) qualify for compensatory benefits because


        1
       Addison died during the pendency of this case, and his
widow, Shirley Addison, was substituted as the party in
interest.


                                                   2
they suffer from coal dust-related pulmonary injuries, commonly

categorized as pneumoconiosis.                See 30 U.S.C. §§ 901-944.              The

implementing     regulations        define     pneumoconiosis    as        a    “chronic

dust disease of the lung and its sequelae, including respiratory

and pulmonary impairments, arising out of coal mine employment.”

20 C.F.R. § 718.201(a).

     Courts    recognize      two     forms    of    pneumoconiosis:       “clinical”

and “legal.”     See Clinchfield Coal Co. v. Fuller, 180 F.3d 622,

625 (4th Cir. 1999). 2        Clinical pneumoconiosis “consists of those

diseases recognized by the medical community as pneumoconiosis,

i.e., the conditions characterized by permanent deposition of

substantial amounts of particulate matter in the lungs and the

fibrotic reaction of the lung tissue to that deposition caused

by   dust    exposure    in    coal    mine     employment.”          20       C.F.R.    §

718.201(a)(1).       Legal pneumoconiosis, by contrast, “encompasses

a wide variety of conditions . . . whose etiology is not the

inhalation of coal dust, but whose respiratory and pulmonary

symptomatology have nonetheless been made worse by coal dust

exposure.”     Clinchfield, 180 F.3d at 625.               The regulations thus

define   legal   pneumoconiosis         as    “any    chronic   lung       disease      or

impairment     and      its   sequelae         arising    out    of        coal    mine

employment.”     20 C.F.R. § 718.201(a)(2).

     2 This opinion omits internal marks, alterations, citations,
emphasis, or footnotes from quotations unless otherwise noted.


                                          3
      To obtain black lung benefits under the Act, a claimant

must prove by a preponderance of the evidence that: “(1) he has

[either kind of] pneumoconiosis; (2) the pneumoconiosis arose

out of his coal mine employment; (3) he has a totally disabling

respiratory or pulmonary condition; and (4) pneumoconiosis is a

contributing         cause       to     his     total      respiratory         disability.”

Milburn    Colliery        Co.    v.    Hicks,      138    F.3d    524,    529      (4th    Cir.

1998).        The    parties          agreed     that      Addison      suffered        from     a

disabling       respiratory             condition          that      prevented          further

employment.          The     issue       below,      and     on    review,        is    whether

Addison’s disability was the result of pneumoconiosis arising

out of his coal mine employment.                    The dispute centers around the

exclusion and consideration of certain medical evidence and the

ALJ’s conclusions in evaluating the expert medical opinions.

      A claimant may establish the existence of pneumoconiosis

by,     among    other       means,      chest      x-rays        and     medical       opinion

evidence.       See 20 C.F.R. § 718.202(a).                        In addition, “[t]he

results of any medically acceptable test or procedure . . . ,

which     tends      to      demonstrate         the      presence        or   absence          of

pneumoconiosis . . . may be submitted in connection with a claim

and   shall     be   given       appropriate        consideration.”            20      C.F.R.    §

718.107(a).          Although          the     regulations        group     the     forms       of

permissible evidence into discrete categories, an ALJ must weigh

all of the evidence together when determining whether the miner

                                                4
has   established        the    presence   of    pneumoconiosis.      See   Island

Creek Coal Co. v. Compton, 211 F.3d 203, 208-09 (4th Cir. 2000).



                                           II.

                                           A.

      Addison worked in the coal industry for approximately 12

years. 3      Prior to abandoning this line of work in 1981 due to a

neck fracture and arthritis, his employment consisted of stints

as a general laborer, scoop operator, and finally foreman with

Sea-B.        As often occurs in these cases, Addison was a cigarette

smoker, and his smoking history far exceeds the length of his

mining career.           Addison began his pack-a-day smoking habit in

1956 and stopped sometime between 2001 and 2012.                   The evidence

is clear that Addison suffered from a myriad of ailments during

the latter part of his life that, if not caused by smoking, were

certainly amplified by this activity.                 Among other things, he

had       a    history     of     arthritis,      coronary   artery     disease,

hypertension, and diabetes.




      3Addison attested that he worked in the mines for 13 years.
The parties have stipulated, however, that the length of his
coal-mining career was actually 11.7 years.



                                            5
       In March 2011, Addison filed the present claim for living

miner benefits. 4        His case was referred to a claims manager, who

found that Addison was entitled to benefits due to his prior

coal       employment.           Sea-B   disputed       the     award       and        sought

administrative review before an ALJ.

       At    the   ensuing        hearing,       Addison     testified           about    his

employment history, explaining that he worked in “very thick

dust” while at the mines.            J.A. 52.        He also testified about his

decade of breathing problems, for which he had been prescribed

oxygen and other pulmonary medications.                       Apart from Addison’s

testimony,      the      parties     introduced       various        medical       evidence

concerning         his         condition,        including          (1)      conflicting

interpretations       of       several   chest     x-rays;     (2)    three       CT     scans

which all read negative for pneumoconiosis; (3) the results from

pulmonary function tests and arterial blood gas studies; (4)

hospitalization          and    treatment        records;     and     (5)    conflicting

medical      opinions      from     three        physicians,        Dr.     J.     Randolph

Forehand, Dr. Gregory J. Fino, and Dr. James R. Castle, all of


       4
       Addison first requested black lung benefits in 2004, but
his claim was denied for failure to show a totally disabling
respiratory impairment.      The instant case is a “subsequent”
claim subject to denial absent proof of a change in the
applicable    condition   of  entitlement  that  was   unfavorably
adjudicated.    20 C.F.R. § 725.309(c).   The ALJ determined that
Addison had demonstrated such a change, in that he had become
totally    disabled,    and   Sea-B   has  not   challenged   this
determination on appeal.


                                             6
whom agreed that Addison was totally disabled by a respiratory

impairment but differed as to its cause and type.

       Dr.     Forehand,       who     performed         the    Department         of    Labor

sponsored       examination,           diagnosed        Addison       as     having       both

pneumoconiosis and a non-disabling ventilatory impairment caused

by cigarette smoking.                His opinion was based on an arterial

blood gas study showing impaired gas exchange during exercise, a

single 2011          chest    x-ray,    and   Addison’s         history     of    coal    dust

exposure.       Had Addison not worked in the mines, Dr. Forehand

opined, “his arterial blood gas would no doubt be normal and his

chest x-ray clean.”            J.A. 104.

       Dr.    Fino     diagnosed       Addison    with     “idiopathic        interstitial

fibrosis” that, although disabling, is “unrelated to coal dust

inhalation.”          J.A. 154.        As support for this opinion, Dr. Fino

cited    the    “marked        progression”        of    Addison’s         lung    condition

between       2008     and    2011,      as   evidenced         by    the     photographic

progression in the CT scans and x-rays.                        J.A. 153.     He explained

that    the    worsening        of     Addison’s        illness      “occurred      far     too

rapidly to be consistent with coal-mine-dust inhalation.”                                 J.A.

205.      Dr. Fino further testified that although coal workers’

pneumoconiosis          can     cause     pulmonary        fibrosis,         the        medical

evidence did not support such a diagnosis here.                                   “Coal dust

causes nodular fibrosis,” Dr. Fino explained, “[w]hereas this

fibrosis [Addison] has is a diffuse type” which is “completely

                                              7
different pathologically and radiographically.”                     J.A. 213.      Dr.

Fino   also    noted     that    Addison’s      fibrosis     was    restrictive    in

nature, which is not characteristic of pneumoconiosis.                      Finally,

Dr. Fino averred that he was in the best position to assess

Addison’s condition because he had the benefit of reviewing lung

imagery over time, whereas Dr. Forehand had only conducted “a

one-time review of a chest x-ray.”               J.A. 207.

       Dr.    Castle     reached    a    similar    conclusion      as     Dr.   Fino,

opining      that      Addison     suffered      from    idiopathic        pulmonary

fibrosis.       After reviewing essentially the same evidence, Dr.

Castle explained that these tests revealed “linear, irregular

type    opacities        which     are   not     typical     of     coal    workers’

pneumoconiosis.”         J.A. 267-68.          Dr. Castle further noted that

idiopathic pulmonary fibrosis is a disease of unknown cause but

is associated with heavy cigarette smoking and not coal dust

exposure.

                                          B.

       In    deciding     that   Addison       established    the    existence     of

pneumoconiosis, the ALJ evaluated several items of conflicting

medical evidence.         He first considered the x-ray evidence, which

consisted of three chest images dated January 2009, February

2011, and May 2011.              The ALJ found the first two x-rays in

equipoise      as   to     the     existence       of   pneumoconiosis       because

similarly qualified doctors rendered conflicting interpretations

                                           8
for each.         As to the May 2011 x-ray, the ALJ noted that “Dr.

Forehand         and   Dr.     Miller      interpreted         it    as    positive      for

pneumoconiosis . . . , while Dr. Scott interpreted the same x-

ray as negative for pneumoconiosis.”                       J.A. 12. 5      Observing that

Drs. Miller and Scott were both equally qualified “B-readers and

board-certified radiologists,” the ALJ determined that the “May

20,     2011      chest       x-ray   is     overall        positive       for    clinical

pneumoconiosis”           because     Dr.      Miller’s       positive        reading     was

“supported by Dr. Forehand’s opinion.”                       Id.     Dr. Forehand is a

certified B-reader but not a radiologist. 6

      The ALJ next considered the CT scan evidence and noted such

scans       do   not   fall    within    the       category    of    traditional        x-ray

evidence,        and   consequently        they     “must     be    weighed    with     other

acceptable medical evidence under 20 C.F.R. § 718.107.”                                  J.A.

13-14.        The ALJ further interpreted the regulations as allowing

“only one reading of ‘other evidence’ such as CT scans.”                                J.A.

14.         Accordingly,      although     Sea-B     had    offered       three   CT    scans


        5
        Drs. Miller and Scott offered testimony regarding
Addison’s chest x-rays but did not submit further opinion
evidence as to his condition.

        6
       The record also contained a digital x-ray of Addison’s
chest dated October 20, 2011.   While Dr. Fino opined that this
x-ray was negative for pneumoconiosis, the ALJ rejected this
interpretation   as   inconsistent   with    the   “implementing
regulations.”  J.A. 13 (citing 20 C.F.R. §§ 718.102, 718.202).
Consequently, the ALJ did not consider this x-ray evidence in
its analysis. Sea-B has not challenged this ruling on appeal.


                                               9
spanning     2008     to    2012,       all       with     negative       readings     for

pneumoconiosis, the ALJ determined Sea-B was entitled to admit

only one scan.         Without explanation, the ALJ picked Addison’s

July 2012 CT scan, which showed “no changes consistent with a

coal mine dust associated occupational disease,” as evaluated by

Dr. Fino.    Id.     Because Dr. Fino’s testimony was undisputed, the

ALJ concluded that “the CT scan evidence d[id] not support a

finding of clinical or legal pneumoconiosis.”                      Id.

      After discounting Addison’s treatment and hospital records

as   non-probative,        the    ALJ    lastly      turned      to    the   conflicting

medical opinions from Drs. Forehand, Fino, and Castle.                            The ALJ

accorded    the     most   weight       to   Dr.     Forehand,        finding   his   view

consistent with the Department of Labor’s position that coal

dust exposure and cigarette smoking are additive in producing

significant airway obstruction.                   J.A. 20.       On this point, the

ALJ referenced 65 Fed. Reg. 79,940 (Dec. 20, 2000), which notes

that “[c]oal dust exposure is additive with smoking in causing

clinically        significant        airways         obstruction          and     chronic

bronchitis.”         The   ALJ     further        found    Dr.    Forehand’s      opinion

supported by unidentified “diagnostic testing.”                        J.A. 20.

      The ALJ discredited the opinions of Drs. Fino and Castle

for several reasons.             He found, among other things, that their

diagnoses    overemphasized         the       fact       that    Addison’s      pulmonary

impairment was restrictive in nature, rather than obstructive,

                                             10
when       evaluating          the       existence         of        pneumoconiosis.                   The

regulations, on the other hand, state that legal pneumoconiosis

includes         “any    chronic         restrictive            or       obstructive         pulmonary

disease      arising       out      of     coal    mine    employment.”                20    C.F.R.      §

718.201(a)(2).             The       ALJ    also        found    the       opinions         “based     on

generalities,           rather       than    focusing       on       [Addison’s]           condition.”

J.A. 19.         In the end, the ALJ concluded that the medical opinion

evidence weighed in Addison’s favor.

       Specifically            crediting          his     determination               of    the    x-ray

evidence and Dr. Forehand’s report over the remaining record,

the ALJ found that Addison had established the existence of both

clinical         and    legal       pneumoconiosis         by        a   preponderance            of   the

evidence.          After further finding that Addison’s pneumoconiosis

arose      out     of    his     prior      employment          and       was     a    substantially

contributing cause of his disability, the ALJ awarded benefits

under the Act.

                                                   C.

       Sea-B       filed       an    administrative         appeal          with       the    Benefits

Review Board (“Board”), specifically disputing the ALJ’s finding

that       the     medical          evidence       established              the       existence         of

pneumoconiosis. 7          In a split decision, the Board affirmed.


       7
       Sea-B also challenged whether the medical evidence was
sufficient to establish disability causation pursuant to 20
C.F.R. § 718.204(c).   Sea-B has not raised this issue in its
(Continued)
                                                   11
       Agreeing with Sea-B, the majority conceded that the ALJ

“erred in considering only one of the three CT scans [Sea-B]

submitted       in    its    affirmative         case.”         J.A.       30.         Ultimately,

however, the majority declined to vacate the award, finding that

Sea-B failed to show this error was harmful.                               Id.     They faulted

Sea-B   for     not    proffering       a    “specific          explanation            of   how    the

[ALJ’s] error could have made a difference.”                                Id.        The dissent

took    issue    with       this   conclusion,          explaining             that,    “[b]y      the

majority’s       reasoning,        improper           exclusion        of       evidence       would

always be harmless error because it is not possible to determine

with    certainty       its     effect      on        the   trier-of           fact’s       ultimate

determination.”             J.A.     34.         Given      this      error,       the       dissent

explained,       the    ALJ’s      “overall           finding    of     the       existence        of

pneumoconiosis . . . is tainted” and should be sent back.                                         J.A.

35.

       The majority also rejected Sea-B’s arguments against the

ALJ’s method of weighing the medical evidence.                                  In response to

Sea-B’s    contention         that    the        ALJ     impermissibly            resolved         the

conflicting      x-ray       evidence       by    resorting        to      a    headcount,         the

Board concluded that he “properly considered the weight of the

positive        x-ray        readings            in     light         of         the        readers’




petition, thus waiving further judicial review.       See United
States v. Al-Hamdi, 356 F.3d 564, 571 n.8 (4th Cir. 2004).


                                                 12
qualifications.”           J.A.   28.     The    Board      further     sustained    the

ALJ’s decision to accord “less weight to [Dr. Fino’s and Dr.

Castle’s] opinions because the[se] physicians were not able to

adequately explain the bases for their conclusions.”                      J.A. 32.

      Following      the   Board’s      unfavorable       decision,     Sea-B   timely

filed the instant petition for review.                       We have jurisdiction

under 33 U.S.C. § 921(c).



                                         III.

      Our review of a decision awarding black lung benefits is

“limited.”      Harman Mining Co. v. Dir., OWCP, 678 F.3d 305, 310

(4th Cir. 2012).        We evaluate the legal conclusions of the Board

and ALJ de novo but defer to the ALJ’s factual findings if

supported by substantial evidence.                    See Hobet Mining, LLC v.

Epling, 783 F.3d 498, 504 (4th Cir. 2015) (“We ask only whether

substantial evidence supports the factual findings of the ALJ

and   whether    the    legal     conclusions        of   the   Board    and   ALJ   are

rational and consistent with applicable law.”).                          “Substantial

evidence is more than a mere scintilla.                     It means such relevant

evidence   as    a     reasonable       mind    might     accept   as    adequate    to

support a conclusion.”            Consol. Edison Co. of N.Y. v. NLRB, 305

U.S. 197, 229 (1938).

      Applying    this      standard,     we    do    not    undertake    to    reweigh

contradictory medical evidence, make credibility determinations,

                                          13
or substitute our judgment for that reached below.                         Rather, the

duty to resolve conflicts in the evidence rests with the ALJ as

factfinder.      And   when      conflicting        evidence      allows    reasonable

minds to differ as to whether a claimant is disabled or has

pneumoconiosis, the responsibility for that decision falls on

the ALJ.   See Harman Mining Co., 678 F.3d at 310.

      That said, our deference to an ALJ’s factual findings is

not   unlimited.       An   ALJ       must    still    conduct     “an     appropriate

analysis of the evidence to support his conclusion.”                             Milburn

Colliery Co., 138 F.3d at 529.                    As this Court has previously

explained, “[u]nless the [ALJ] has analyzed all evidence and has

sufficiently     explained       the       weight     he    has    given    to    [the]

exhibits, to say that his decision is supported by substantial

evidence     approaches     an    abdication          of   the    court’s     duty   to

scrutinize    the   record       as    a   whole     to    determine     whether     the

conclusions reached are rational.”                  Sterling Smokeless Coal Co.

v. Akers, 131 F.3d 438, 439-40 (4th Cir. 1997).                        Thus, “[e]ven

if legitimate reasons exist for rejecting [or crediting] certain

evidence, the [ALJ] cannot do so for no reason or for the wrong

reason.”     King v. Califano, 615 F.2d 1018, 1020 (4th Cir. 1980).

Where an ALJ has incorrectly weighed the evidence or failed to

account for relevant record evidence, deference is not warranted

and remand is frequently required.                 See Island Creek Coal Co. v.

Compton, 211 F.3d at 213.

                                             14
       Furthermore, as a condition to appellate review, an ALJ

must “adequately explain why he credited certain evidence and

discredited other evidence.”                Milburn Colliery Co., 138 F.3d at

533; see also Consolidation Coal Co. v. Filer, No. 95-1270, 1996

WL    139196,   at    *5    (4th     Cir.    Mar.       26,    1996)    (“Decisions     on

conflicting evidence . . . must be addressed and explained at

the    administrative        level     before       judicial      review       under    the

substantial          evidence         standard           can      be         accomplished

meaningfully.”).          Although this requirement “is not intended to

be a mandate for administrative verbosity,” a reviewing court

must   be   able     to    “discern    what       the   ALJ    did     and   why   he   did

it.”     Piney Mountain Coal Co. v. Mays, 176 F.3d 753, 762 n.10

(4th Cir. 1999).

       With this standard of review as the backdrop, we turn to

Sea-B’s arguments.



                                            IV.

                                            A.

       Sea-B    initially       contends         that    the     ALJ’s       decision   to

consider only one of the three CT scans included in the record

was error requiring reversal of the ALJ’s judgment.                                Addison

does not argue in favor of the ALJ’s evidentiary ruling; rather,

like the Board, he contends Sea-B failed to show this error was

prejudicial.

                                            15
        We agree with the parties and the Board that the ALJ erred:

Sea-B    was    entitled       to     submit,        and    the   ALJ      was    required     to

consider, one reading of each CT scan under 20 C.F.R. § 718.107.

The remaining issue is whether Sea-B is entitled to any relief

for that error.

       Sea-B     appears       to     contend        that     this      evidentiary         error

requires remand without further inquiry.                          On brief, Sea-B argued

that     when    an     ALJ    fails       to    review       all     relevant         evidence,

“[a]ppellate       review      is     impossible.”            Opening       Br.    21.        This

argument sweeps too broadly.                    Administrative adjudications are

subject to the same harmless error rule that generally applies

to civil cases.          Reversal on account of error is not automatic

but requires a showing of prejudice.                        See Consolidation Coal Co.

v. Williams, 453 F.3d 609, 621-22 (4th Cir. 2006).                                The harmless

error    rule    applies       to    agency     action       because       if    the   agency’s

mistake did not affect the outcome, it would be senseless to

vacate and remand for reconsideration.                        The rule of prejudicial

error     further        prevents          reviewing          courts        from        becoming

“impregnable          citadels        of     technicality”           and        preserves     the

relative        roles     of        courts      and        agencies        in     implementing

substantive      policy.            Shinseki     v.    Sanders,       556       U.S.   396,   407

(2009).

       The burden to demonstrate prejudicial error is on Sea-B,

the party challenging the agency action.                          Id. at 409.           However,

                                                16
the harmless error rule is “not . . . a particularly onerous

requirement.”      Id. at 410.        As the Supreme Court has explained,

“[o]ften the circumstances of the case will make clear to the

appellate judge that the ruling, if erroneous, was harmful and

nothing   further      need   be    said.”         Id.        Our    determination        of

prejudice      ultimately     requires        “case-specific              application      of

judgment, based upon examination of the record,” not “mandatory

presumptions and rigid rules.”                Id. at 407.            In each case, an

appellate court must consider “the likelihood that the result

would   have    been   different,”     as     well       as   how     the    error      might

impact the public perception of such proceedings.                          Id. at 411.

     In claiming that the error here was not harmless, Sea-B

relies on our decision in Island Creek Coal Co. v. Compton,

where we held “all relevant evidence is to be considered” in

evaluating a claim for black lung benefits.                          211 F.3d at 208.

Selecting this language out of context, Sea-B posits that the

ALJ’s failure to evaluate the full spectrum of CT scan evidence

is per se prejudicial.          We cannot agree.               Sea-B’s proposed per

se rule is contrary to the Supreme Court’s direction not to

determine   prejudice       through    “mandatory         presumptions            and   rigid

rules.”        Shinseki,      556   U.S.      at    398.            The     use    of    such

presumptions,      the      Court     explained,          “exhibit[s]             the   very

characteristics that Congress sought to discourage,” because it

prevents the court “from resting its conclusion on the facts and

                                         17
circumstances          of     the      particular         case.”          Id.      at   408.

Furthermore, Sea-B has not suggested any basis for concluding

that    an    ALJ’s     failure      to     evaluate      every    piece    of     relevant

evidence will always shape the outcome.                       For example, we could

hardly find prejudice where the excluded evidence was merely

cumulative       or    concerned       an    uncontested     point.         See    Hall    v.

Arthur, 141 F.3d 844, 850 (8th Cir. 1998) (“The exclusion of

cumulative evidence, of course, is merely harmless error.”).

       Although we reject Sea-B’s proposed per se rule, we agree

that    the    ALJ’s        decision    to    exclude      the     additional      CT   scan

evidence was not harmless.                  This error affects the determination

of both clinical and legal pneumoconiosis and impacts the ALJ’s

consideration of the other evidence in this case.

       The omitted CT scan evidence is unquestionably probative of

the    central      issue     in    dispute:       whether   Addison       suffered     from

pneumoconiosis.              Considered       in   aggregate,       the    scans    show   a

timeline of the progression of Addison’s condition that neither

Dr. Forehand nor the ALJ addressed.                       As explained by Dr. Fino,

this progression “occurred far too rapidly to be consistent with

coal-mine-dust inhalation.”                  J.A. 205.       While the ALJ was not

bound to accept this conclusion, he was required to consider it

and    explain        why    he    found      other    evidence      more       persuasive.

Although      the     ALJ     acknowledged         that    such    evidence       “must    be



                                              18
weighed with other acceptable medical evidence,” J.A. 13-14, he

failed to undertake that task.

       When    the     record        contains          the    results      of      a    medically

acceptable         test       that          is      probative         of     pneumoconiosis,

particularly         where    it       is        uncontested,        the   factfinder           must

consider that evidence in his analysis.                            See Dixie Fuel Co., LLC

v. Dir., OWCP, 700 F.3d 878, 880 (6th Cir. 2012); Shelton v. Old

Ben    Coal    Co.,     933       F.2d      504,       507   (7th     Cir.      1991).          That

obligation went unfulfilled here, as the ALJ failed altogether

to weigh the CT scan evidence against the remaining record in

his decision.          And this error had multiple ramifications.                                 By

excluding the CT scans, the ALJ was unable to properly weigh the

CT    scan    evidence       as    a     whole,        particularly        as    probative        of

idiopathic pulmonary fibrosis and exclusive of pneumoconiosis.

Further, the CT scans would have contradicted the ALJ’s findings

as     to    the   x-ray      evidence.                Consequently,         the       ALJ     never

considered, much less explained, how the CT scan evidence would

weigh against the x-ray evidence or impact his consideration of

the overall record.               See Milburn Colliery Co., 138 F.3d at 531

(explaining the general rule that an ALJ must “consider all the

relevant evidence presented”).

       In a related way, the exclusion of the CT scan evidence

rendered the ALJ’s consideration of the medical opinions of Drs.

Fino    and    Castle     inadequate.               The      ALJ    correctly          noted    that

                                                  19
“[w]hen CT scans are evaluated by qualified experts . . . they

are   important       diagnostic     tools      that    have   resulted         in    major

improvements in the assessment of occupational lung disease.”

J.A. 14.      And the ALJ credited both Drs. Fino and Castle as such

experts.        However, the ALJ never considered the importance of

the CT scan timeline to the opinions of Drs. Fino and Castle.

See J.A. 153, 267-69.              The two doctors tied their progression

diagnosis to extensive support in the medical literature and

other physical tests, none of which the ALJ addressed.                               Again,

the ALJ is not required to accept the medical diagnosis that is

shown    by     the   CT   scans    and    their       analysis      in   the    medical

opinions.        But he is required to consider that evidence and

explain the reasons for finding another analysis entitled to

more weight.          See King, 615 F.2d at 1020 (“Even if legitimate

reasons exist for rejecting or discounting certain evidence, the

[ALJ] cannot do so for no reason or for the wrong reason.”).

Thus, by erroneously excluding the CT scan evidence, the ALJ’s

opinion    was    significantly      flawed      on    all   these    fronts         to   the

prejudice of Sea-B.

      We have previously recognized that prejudice is a natural

effect of an error of this kind.                See Consolidation Coal Co. v.

Brown, 230 F.3d 1351 (4th Cir. 2000); Island Creek Coal Co. v.

Groves, 246 F. App’x 842, 846 (4th Cir. 2007); see also Eastover

Mining    Co.    v.    Williams,     338   F.3d       501,   508   (6th    Cir.       2003)

                                           20
(stating where “an ALJ has improperly characterized the evidence

or failed to account [for] relevant record material, deference

is    inappropriate         and    remand     is   required”).         And     here,    that

prejudice is magnified because it is intertwined with the ALJ’s

findings as to the x-ray evidence and the medical opinions, not

just the CT scan evidence.

       Given        that     the     record        is     otherwise      comprised       of

contradictory         evidence        regarding         Addison’s     diagnosis,       this

excluded       evidence      could     have    materially        affected      the     ALJ’s

decision.         See, e.g., Carnevale v. Gardner, 393 F.2d 889, 891

(2d Cir. 1968) (“[I]t is clear that in summarizing and sifting

the evidence in this case, the Hearing Examiner totally ignored

a major piece of evidence which might well have influenced his

decision.       We cannot fulfill the duty entrusted to us . . . if

we cannot be sure that he considered some of the more important

evidence presented[.]”).               Rather than assessing and rejecting a

single negative CT scan, the ALJ should have weighed all three

negative CT scans along with the other credited evidence.

       The error was not harmless and warrants remand to ensure

the    ALJ   fully        considers    the     entire      record,     particularly      in

relation     to     the     opinions    of    Drs.      Fino    and   Castle,    who,    as

discussed      in    more    detail    below,      both    found      that   these     scans

affected the evaluation of the x-ray evidence and discredited a

diagnosis      of    pneumoconiosis.           See      Stout   v.    Comm’r    Soc.    Sec.

                                              21
Admin., 454 F.3d 1050, 1056 (9th Cir. 2006) (explaining that an

error is harmless only if a court can conclude with confidence

that “no reasonable ALJ, when fully crediting the testimony,

could have reached a different [result]”).

                                               B.

       Sea-B        next     argues    that    the     ALJ    erred      by     utilizing     a

headcount of the x-ray readings to conclude Addison suffered

from    pneumoconiosis.                Because      the   record      is      insufficiently

developed         to   permit    appellate       review      of   this     issue,     we   must

vacate and remand for the ALJ to provide an explanation for his

decision.           See Consolidation Coal Co., 1996 WL 139196, at *5

(“Decisions on conflicting evidence . . . must be addressed and

explained         at   the    administrative        level     before       judicial      review

under       the    substantial        evidence      standard      can      be   accomplished

meaningfully.”).

       As     noted,       the   ALJ    considered        three    chest        x-rays     dated

January 12, 2009, February 23, 2011, and May 20, 2011, in his

pneumoconiosis analysis.                He found the first two “in equipoise

as     to     the      existence       of     pneumoconiosis”           because      “equally

qualified”          B-reader     radiologists          had    rendered          contradictory

opinions on each image.                 See J.A. 12.          Turning to the May 20,

2011        x-ray,      however,        the      ALJ      found     it        positive      for

pneumoconiosis and stated the following:



                                               22
            There were three readings of the most recent
            x-ray taken on May 20, 2011.       Dr. Forehand
            and Dr. Miller interpreted it as positive
            for pneumoconiosis . . . , while Dr. Scott
            interpreted the same x-ray as negative for
            pneumoconiosis.    Dr. Forehand is a B reader
            but not board certified in radiology.      Drs.
            Scott and Miller are both dually qualified
            as      B-readers      and      board-certified
            radiologists. Dr. Miller’s opinion that the
            x-ray     is      positive     for     clinical
            pneumoconiosis     is    supported    by    Dr.
            Forehand’s opinion.      Consequently, I find
            that the May 20, 2011, chest x-ray is
            overall       positive       for       clinical
            pneumoconiosis.

J.A. 12.

     Sea-B asserted before the Board that the ALJ did not weigh

this evidence on a valid basis, but instead resolved the issue

by a headcount of expert witnesses.            The Board disagreed and

upheld     the    ALJ’s    conclusion,    stating    that        he     “properly

considered the weight of the positive x-ray readings in light of

the readers’ qualifications.”         J.A. 28.       The record basis the

Board referenced was its statement “that the May 20, 2011 x-ray

evidence    was   positive   for   pneumoconiosis,    as    it    was    read   as

positive by both Dr. Miller and Dr. Forehand, and as negative

only by Dr. Scott.”       J.A. 28.

     When engaged in fact finding, administrative agencies may

not base a decision on the numerical superiority of the same

items of evidence.        See Sterling Smokeless Coal Co., 131 F.3d at

441 (“By resolving the conflict of medical opinion solely on the


                                     23
basis    of       the     number   of     physicians        supporting            the    respective

parties, the ALJ below committed . . . error[.]”).                                  In assessing

such    evidence,          the   ALJ     must    articulate           specific          reasons    and

provide support for favoring one medical reading over another.

See Milburn Colliery Co., 138 F.3d at 536; see also Mitchell v.

OWCP, 25 F.3d 500, 508 (7th Cir. 1994) (observing that an ALJ

may     not       substitute       his    judgment          for       that    of    the        medical

evidence).          We have rejected the practice of simply resorting to

a numerical headcount as “hollow” and not consistent with an

ALJ’s duties in making a reasoned decision.                                    Adkins v. Dir.,

OWCP, 958 F.2d 49, 52 (4th Cir. 1992); see also Mullins Coal

Co., Inc. of Va. v. Dir., OWCP, 484 U.S. 135, 149 n.23 (1987)

(explaining that an ALJ must “weigh the quality, and not just

the quantity, of the evidence”).

       We cannot decipher from the ALJ’s sparse explanation how,

or if, he weighed the x-ray readings in light of the readers’

qualifications.            To conduct appellate review, we must be able to

identify          that    the    ALJ     “has    analyzed            all     evidence      and     has

sufficiently             explained       the    weight          he    has     given       to    [the]

exhibits.”              Sterling     Smokeless        Coal       Co.,       131    F.3d    at     439.

Without       a    more     specific       record      of       the    ALJ’s       rationale       for

reaching his decision as to the May 20 x-ray, we are unable to

adequately perform our judicial review function to assure that

the     ALJ’s       decision       is    based        on    a     “reasoned        explanation.”

                                                 24
Adkins, 958 F.2d at 52.                We cannot guess at what the ALJ meant

to   say,    but    didn’t      because     “[e]stablished       precedent        dictates

that a court may not guess at what an agency meant to say, but

must instead restrict itself to what the agency actually did

say.”    Nken v. Holder, 585 F.3d 818, 822 (4th Cir. 2009).

       Consequently,           on    remand,      the    ALJ    should      provide         an

explanation        for   his    decision     concerning        the   May   20    x-ray      by

explaining how he weighed the evidence “in light of the readers’

qualifications”          and    whether     his     conclusion       was    based      on   a

numerical headcount of experts.                   With a “reasoned explanation”

in the record, the court would then be in a position to conduct

appellate review should that issue arise again.                             Adkins, 958

F.2d at 52.

                                             C.

       Lastly, we turn to the ALJ’s consideration of the medical

opinion evidence, particularly in view of the disposition of the

issues involving the CT scan and x-ray evidence.                                As noted,

three    physicians        submitted        reports      regarding     the      cause       of

Addison’s disability.               Dr. Forehand opined that Addison suffered

from    pneumoconiosis              based   on     a     physical     examination           in

combination with Addison’s prior occupational exposure to coal

dust.       Drs. Fino and Castle, on the other hand, agreed that

Addison’s     respiratory           troubles      were    unrelated    to       coal    dust



                                             25
exposure.         The    ALJ       sided     with       Dr.    Forehand,         finding           his

diagnosis worthy of the greatest weight.

      Although     it    is    within       the     ALJ’s      statutory         authority          to

evaluate and       weigh      medical       opinion      evidence,         an    ALJ       may     not

credit or discredit expert testimony “for no reason or for the

wrong reason.”          King, 615 F.2d at 1020; see also Island Creek

Coal Co. v. Compton, 211 F.3d at 211 (“The ALJ must examine the

reasoning     employed        in    a      medical       opinion      in    light           of     the

objective material supporting that opinion, and also must take

into account any contrary test results or diagnoses.”).                                     In the

absence     of    an     adequate          explanation         supporting             the        ALJ’s

evaluation,       “to    say        that     his        decision      is        supported           by

substantial      evidence      approaches          an    abdication        of        the    court’s

duty to scrutinize the record as a whole to determine whether

the conclusions reached are rational.”                         Sterling Smokeless Coal

Co., 131 F.3d at 439-40; see also Milburn Colliery Co., 138 F.3d

at   533    (finding     error       where    “the       ALJ    failed          to    adequately

explain why he credited certain evidence and discredited other

evidence”).

      The   ALJ    credited        Dr.     Forehand’s         diagnosis         based       on     its

purported     consistency          with     the      following        passage          from        the

preamble    to    the    amended        regulations:          “Coal   dust           exposure       is

additive with smoking in causing clinically significant airways

obstruction and chronic bronchitis.”                          J.A. 20 (citing 65 Fed.

                                              26
Reg.    79,940       (Dec.     20,    2000)).        It    is     well      settled   that    a

factfinder may consult the Act’s preamble in assessing medical

opinion evidence.              See Harman Mining Co., 678 F.3d at 314-15.

Nevertheless,         the    ALJ     erred    in    relying      on    this      passage    here

because    it       has   no    bearing      on     Dr.    Forehand’s         pneumoconiosis

opinion.

       Although Dr. Forehand diagnosed Addison with an obstructive

impairment, he attributed that impairment solely to cigarette

smoking       and     found     it       non-disabling.           See       J.A.    104.     Dr.

Forehand’s diagnosis of legal pneumoconiosis, instead, was based

on an arterial blood gas study showing weakened gas exchange and

the May 2011 x-ray, which he concluded would have been different

had    Addison       never     been      exposed    to    coal    dust.          However,    Dr.

Forehand never says why he reached that conclusion, particularly

since he never found coal dust exposure related to Addison’s

obstructive         impairment.           Quite     the    opposite,        Dr.    Forehand’s

opinion       contradicts          the     preamble       text,       as    he     found     the

obstructive         respiratory       impairment         was   attributed         entirely    to

smoking without any aggravation from coal dust exposure.

       Because       this      proffered          explanation         for     elevating      Dr.

Forehand’s diagnosis is not supported, the ALJ must reevaluate

that opinion to determine the proper weight it should be given.

See Island Creek Coal Co. v. Compton, 211 F.3d at 211-12; King,

615    F.2d     at    1020      (“Even       if    legitimate         reasons      exist     for

                                              27
rejecting or discounting certain evidence, the [ALJ] cannot do

so for no reason or for the wrong reason.”).

     As    noted    earlier,      the      ALJ’s    error     as   to    the    CT   scan

evidence (and the uncertainty as to the validity of the ALJ’s

determination on the x-ray evidence) render his consideration of

the opinions of Drs. Fino and Castle infirm.                            Their opinions

explain in detail, with extensive test and medical literature

support,    why    they    conclude     Addison        had    idiopathic       pulmonary

fibrosis instead of coal workers’ pneumoconiosis.                        A substantial

basis     for   those     opinions      was     the    progressive        timeline    of

Addison’s disease, proven by the chronology of CT scans and x-

rays, that established idiopathic pulmonary fibrosis.                          While the

ALJ was not required to accept their opinions, he could not have

made a reasoned decision evaluating the opinions in view of the

foundational errors regarding the medical evidence.

     Finally,       we     note      the      ALJ      ignored     the        respective

qualifications      of    these   physicians          in   reaching     his    decision.

Dr. Forehand is a board-certified pediatrician and allergist,

whereas    Drs.    Fino    and    Castle        are    both    board-certified        in

internal medicine and pulmonary disease.                      “A primary method of

evaluating the reliability of an expert’s opinion is of course

his expertise[.]”         Adkins, 958 F.2d at 52.              The ALJ should have

given some reasoned explanation as to why Dr. Fino’s and Dr.



                                           28
Castle’s superior qualifications did not carry any weight in his

evaluation.    See Milburn Colliery Co., 138 F.3d at 536.

      The    ALJ’s    finding     that        Addison      suffered       from        legal

pneumoconiosis       relied    heavily     on      the    weight     given       to    Dr.

Forehand’s    opinion      over   that   of      Drs.     Castle    and    Fino.        As

explained several ways above, however, the error as to the CT

scan evidence fundamentally affected the ALJ’s capacity to reach

that conclusion.       The ALJ failed to analyze all of the relevant

evidence and give a reasoned explanation for how it was weighed.

Sterling, 131 F.3d at 439-40 (“Unless the [ALJ] has analyzed all

evidence and has sufficiently explained the weight he has given

to [the] exhibits, to say that his decision is supported by

substantial    evidence       approaches      an   abdication       of    the    court’s

duty to scrutinize the record as a whole to determine whether

the   conclusions     reached     are    rational.”).              Consequently,        we

conclude these errors were prejudicial to Sea-B because without

them the likelihood that the result would have been different is

significant.         See   Shinseki,       556     U.S.    at   410       (“Often      the

circumstances of the case will make clear to the appellate judge

that the ruling, if erroneous, was harmful and nothing further

need be said.”).




                                         29
                                V.

      For all these reasons, we grant the petition for review,

vacate the Board’s decision, and remand with instructions for

the   Board   to   return   Addison’s    case   to   the   ALJ   for

reconsideration consistent with this opinion.



                                        PETITION FOR REVIEW GRANTED;
                                          ORDER VACATED AND REMANDED




                                30
