FILED

U.S. COURT OF APPEALS

ELEVENTH CIRCUIT

 FEBRUARY 23, 2012

JOHN LEY

CLERK

 [DO NOT PUBLISH]

IN THE UNITED STATES COURT OF APPEALS

 FOR THE ELEVENTH CIRCUIT

 ________________________

 No. 11-12450 

Non-Argument Calendar

 ________________________

 D.C. Docket No. 1:10-cv-22263-MGC

RICARDO M. SIVERIO, 

 llllllllllllllllllllllllllllllllllllllllPlaintiff-Appellant,

versus

COMMISSIONER OF SOCIAL SECURITY, 

 llllllllllllllllllllllllllllllllllllllllDefendant-Appellee.

________________________

 Appeal from the United States District Court

 for the Southern District of Florida

 ________________________

(February 23, 2012)

Before BARKETT, MARTIN and ANDERSON, Circuit Judges.

PER CURIAM:

Ricardo Siverio appeals the district court’s order affirming the denial under
42 U.S.C. § 405(g) of his application for disability insurance benefits by Social

Security Commissioner Michael Astrue. On appeal, Siverio argues that the

Administrative Law Judge (“ALJ”) erred by finding that he retained the residual

functional capacity (“RFC”) to perform medium work. He also argues that the

ALJ erred by discounting the opinion of his treating physician, Dr. Emilio Suarez.

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Upon review of the record and consideration of the parties’ briefs, we reverse in

part and affirm in part.

I.

We review the Commissioner’s factual findings to determine whether they

are supported by substantial evidence. Ingram v. Comm’r of Soc. Sec. Admin.,

496 F.3d 1253, 1260 (11th Cir. 2007). Substantial evidence is defined as “such

relevant evidence as a reasonable person would accept as adequate to support a

conclusion.” Bloodsworth v. Heckler, 703 F.2d 1233, 1239 (11th Cir. 1983). It is

“more than a scintilla, but less than a preponderance.” Id. In conducting this

review, we may not decide facts anew, reweigh the evidence, or substitute our

judgment for that of the ALJ. Dyer v. Barnhart, 395 F.3d 1206, 1210 (11th Cir.

 Additionally, Siverio argues that the ALJ erred by relying on the medical-vocational 1

guidelines, rather than using a vocational expert to determine whether he could perform work

that exists in the national economy. In reversing and remanding, we assume the ALJ will rely on

the guidelines only if substantial evidence supports a finding that nonexertional impairments do

not prevent Siverio from performing a wide range of work at Siverio’s work capacity level. See

Phillips v. Barnhart, 357 F.3d 1232, 1243 (11th Cir. 2004).

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2005). At the same time, we will reverse where the ALJ fails either to apply the

correct law or to “provide [us] with sufficient reasoning for determining that the

proper legal analysis has been conducted.” Keeton v. Dep’t of Health & Human

Servs., 21 F.3d 1064, 1066 (11th Cir. 1994).

II.

A claimant seeking disability insurance benefits must demonstrate that he

was disabled on or before the last date on which he was last insured. Moore v.

Barnhart, 405 F.3d 1208, 1211 (11th Cir. 2005). In this case, Siverio needed to

demonstrate disability on or before December 31, 2008.

The social security regulations establish a five-step, sequential evaluation

process to determine disability for disability benefits claims. See 20 C.F.R.

§ 404.1520. The ALJ must evaluate: (1) whether the claimant engaged in

substantial gainful employment; (2) whether the claimant has a severe impairment;

(3) whether the severe impairment meets or equals an impairment in the Listing of

Impairments; or (4) whether the claimant has the RFC to perform his past relevant

work; and (5) whether, in light of the claimant’s RFC, age, education and work

experience, there are other jobs the claimant can perform. See Phillips v.

Barnhart, 357 F.3d 1232, 1237 (11th Cir. 2004); 20 C.F.R.

§ 404.1520(a)(4)(i)–(v). Throughout the process, the burden is on the claimant to

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introduce evidence in support of his application for benefits. Ellison v. Barnhart,

355 F.3d 1272, 1276 (11th Cir. 2003).

Here, the ALJ found that Siverio was not engaged in substantial gainful

activity, had severe impairments that did not meet or equal a listed impairment,

and could not perform past relevant work. When that happens, the ALJ must then

determine, at step five, whether the claimant’s RFC allows him to perform work

that exists in the national economy. 20 C.F.R. § 404.1520(a)(4)(v), (g). 

RFC is an assessment of a claimant’s remaining ability to do work despite

his impairments. Lewis v. Callahan, 125 F.3d 1436, 1440 (11th Cir. 1997). The

ALJ makes an RFC finding based on all the “relevant medical and other

evidence.” 20 C.F.R. § 404.1545(a)(3). The ALJ must consider any statements by

medical sources about what the claimant can still do and whether those statements 2

are based on formal medical examinations. The ALJ must also consider

descriptions and observations of the limitations resulting from the claimant’s

impairments, including limitations that result from symptoms, such as pain. Id. 

Only “acceptable medical sources” can provide medical opinions, which are

 The term “medical sources” refers to both “acceptable medical sources” and other health 2

care providers who are not “acceptable medical sources.” See 20 C.F.R. § 404.1502.

“Acceptable medical source” includes treating sources, nontreating sources, and nonexamining

sources. Id. The regulations identify “acceptable medical sources” as licensed physicians,

licensed or certified psychologists, licensed optometrists, licensed podiatrists, and qualified

speech-language pathologists. See id. § 404.1513(a).

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“statements from physicians and psychologists or other acceptable medical sources

that reflect judgments about the nature and severity of” a claimant’s impairment,

including symptoms, diagnosis and prognosis, what the claimant can still do

despite the impairment, and the claimant’s physical or mental restrictions. Id.

§ 404.1527(a)(2).

To describe what kind of work a claimant is able to undertake, the RFC

assessment typically adopts one of the following work classifications: sedentary,

light, medium, heavy, and very heavy. Id. § 404.1567. Medium work is defined

as “lifting no more than 50 pounds at a time with frequent lifting or carrying of

objects weighing up to 25 pounds.” Id. § 404.1567(c). Light work involves

“lifting no more than 20 pounds at a time with frequent lifting or carrying of

objects weighing up to 10 pounds.” Id. § 404.1567(b). Sedentary work is defined

as “lifting no more than 10 pounds at a time and occasionally lifting or carrying

articles like docket files, ledgers, and small tools. Although a sedentary job is

defined as one which involves sitting, a certain amount of walking and standing is

often necessary in carrying out job duties.” Id. § 404.1567(a). Social Security

Ruling (“SSR”) 83-10 further elaborates on sedentary work by providing that

“periods of standing or walking should generally total no more than about 2 hours

of an 8-hour workday, and sitting should generally total approximately 6 hours of

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an 8-hour workday.” SSR 83-10, available at 1983 WL 31251.

After thorough review of the record and the parties’ briefs, we conclude that

substantial evidence does not support the ALJ’s finding that Siverio had the RFC

to perform medium work. It is undisputed that the ALJ erroneously relied on the

RFC assessment of Zuleika Martin as a medical opinion, even though Martin was

a “single decision maker” with no apparent medical credential. In Florida, a single

decision maker (“SDM”) is assigned to make the initial disability determination

after “appropriate consultation with a medical or psychological consultant.” See

20 C.F.R. § 404.906(b)(2). But the “SDM” designation connotes no medical

credentials. See id. § 404.906(a), (b)(2). Indeed, the SSA’s Program Operations

Manual System (“POMS”) explicitly distinguishes RFC assessments produced by

an SDM from those produced by a medical consultant, and states that

“SDM-completed forms are not opinion evidence at the appeals level.” POMS

§ DI 24510.050, available at

https://secure.ssa.gov/apps10/poms.nsf/lnx/0424510050. As an SDM with no

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apparent medical credential, Martin was not an acceptable medical source. 

Nonetheless, the ALJ mistakenly treated Martin’s opinion that Siverio could

 We have previously noted that, “[w]hile the POMS does not have the force of law, it can 3

be persuasive.” Stroup v. Barnhart, 327 F.3d 1258, 1262 (11th Cir. 2003).

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perform medium work as the “expert opinion” of a “DDS physician[],” “State

Agency physician[],” and “DDS medical consultant[].”

This was not a harmless error. The ALJ’s opinion shows not only that the

ALJ labored under the mistaken belief that Martin’s RFC assessment had been

authored by a physician, but also that he gave Martin’s RFC assessment

“significant weight.” The remaining record evidence does not provide substantial

evidence for the finding that Siverio was capable of performing medium work. 

Other than Martin’s opinion, which the ALJ erroneously relied upon as a medical

opinion, there is nothing in the record that could have reasonably led the ALJ to

conclude that Siverio could occasionally lift fifty pounds and frequently lift

twenty-five pounds, and thus perform medium work. Thus, it appears it was

primarily on the basis of Martin’s RFC assessment that the ALJ concluded that

Siverio could perform medium work. Because substantial evidence does not

support this finding, we reverse and remand for reconsideration of Siverio’s RFC.

III.

The ALJ must state with particularity the weight given different medical

opinions and the reasons for doing so. Sharfarz v. Bowen, 825 F.2d 278, 279

(11th Cir. 1987). The ALJ may reject any medical opinion if the evidence

supports a contrary finding. Id. Nevertheless, a treating physician’s opinion about

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the nature and severity of a claimant’s impairment is generally given controlling

weight if it is well supported and is not inconsistent with the other substantial

evidence. 20 C.F.R. § 404.1527(d)(2). A treating physician’s opinion is given

“substantial or considerable weight unless ‘good cause’ is shown to the contrary.” 

Phillips, 357 F.3d at 1240. Good cause exists when: (1) the treating physician’s

opinion is not bolstered by the evidence; (2) evidence supports a contrary finding;

or (3) the treating physician’s opinion was conclusory or inconsistent with the

physician’s own medical records. Id. at 1240–41. 

 The ALJ rejected the medical opinion of Siverio’s treating physician, Dr.

Suarez, in so far as the opinion indicated “that the claimant is not capable of

sedentary work.” The ALJ’s explanation for doing so was that Dr. Suarez’s

opinion about Siverio’s capacity to do sedentary work was “not consistent with the

other evidence of record as discussed in the body of the decision.” Siverio argues

this explanation was insufficient to establish good cause for discounting the

opinion of his treating physician. We hold that the ALJ’s articulated reason was

supported by substantial evidence.

In his February 2008 and January 2009 assessments, Dr. Suarez opined that

in an eight-hour workday Siverio could only sit for five hours, stand for two hours,

and walk for one hour. Because sedentary work generally requires being able to

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sit for approximately six hours total in an eight-hour workday, 20 C.F.R. §

404.1567(a); SSR 83-10, Dr. Suarez’s assessments suggested that Siverio may not

be capable of sedentary work.

However, other medical evidence indicated the contrary. For example, Dr.

Muth found that Siverio could stand, sit, or walk for about six hours in an eighthour workday, and was thus capable of sedentary work. In addition, in both

September 2005 and January 2006, Dr. Cohen indicated that Siverio had no

restrictions in his ability to stand, walk, sit, or climb. Thus, there was substantial

record evidence that was inconsistent with Dr. Suarez’s opinion regarding

Siverio’s incapacity to perform the full range of sedentary work. The ALJ

therefore acted within the bounds of his discretion when he discounted Dr.

Suarez’s opinion regarding this specific matter. See Phillips, 357 F.3d at

1240–41. Accordingly, we affirm as to this issue.

REVERSED in part, AFFIRMED in part.

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