20 C.F.R. § 404.1564 : Employees' Benefits — SOCIAL SECURITY ADMINISTRATION — FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) — DETERMINING DISABILITY AND BLINDNESS —VOCATIONAL CONSIDERATIONS — Your education as a vocational factor

(a) General. Education is primarily used to mean formal schooling or other training which contributes to your ability to meet vocational requirements, for example, reasoning ability, communication skills, and arithmetical ability. However, if you do not have formal schooling, this does not necessarily mean that you are uneducated or lack these abilities. Past work experience and the kinds of responsibilities you had when you were working may show that you have intellectual abilities, although you may have little formal education. Your daily activities, hobbies, or the results of testing may also show that you have significant intellectual ability that can be used to work.
(b) How we evaluate your education. The importance of your educational background may depend upon how much time has passed between the completion of your formal education and the beginning of your physical or mental impairment(s) and by what you have done with your education in a work or other setting. Formal education that you completed many years before your impairment began, or unused skills and knowledge that were a part of your formal education, may no longer be useful or meaningful in terms of your ability to work. Therefore, the numerical grade level that you completed in school may not represent your actual educational abilities. These may be higher or lower. However, if there is no other evidence to contradict it, we will use your numerical grade level to determine your educational abilities. In evaluating your educational level, we use the following categories:
(1) Illiteracy. Illiteracy means the inability to read or write. We consider someone illiterate if the person cannot read or write a simple message such as instructions or inventory lists even though the person can sign his or her name. Generally, an illiterate person has had little or no formal schooling.
(2) Marginal education. Marginal education means ability in reasoning, arithmetic, and language skills which are needed to do simple, unskilled types of jobs. We generally consider that formal schooling at a 6th grade level or less is a marginal education.
(3) Limited education. Limited education means ability in reasoning, arithmetic, and language skills, but not enough to allow a person with these educational qualifications to do most of the more complex job duties needed in semi-skilled or skilled jobs. We generally consider that a 7th grade through the 11th grade level of formal education is a limited education.
(4) High school education and above. High school education and above means abilities in reasoning, arithmetic, and language skills acquired through formal schooling at a 12th grade level or above. We generally consider that someone with these educational abilities can do semi-skilled through skilled work.
(c) Information about your education. We will ask you how long you attended school, and whether you are able to understand, read, and write, and do at least simple arithmetic calculations. We will also consider other information about how much formal or informal education you may have had through your previous work, community projects, hobbies, and any other activities which might help you to work.

20 C.F.R. §404.1564

85 FR 10602, 4/27/2020