N/A or sometimes n/a is a common abbreviation in tables and lists for the phrase not applicable, not available, not assessed,  or no answer. It is used to indicate when information in a certain table cell is not provided, either because it does not apply to a particular case in question or because the answer is not available. Such a notation can be used on many different types of forms.
The notation was in use at least as early as the 1920s, with a 1925 guide to conducting community surveys instructing those asking questions for the survey:
Some of the questions on the card are of course not applicable at all times. For instance, a household composed of two widowed sisters living on their income has no wage earner. The survey director should request that the initials "n a" ("not applicable") be written down opposite such questions. No space should be left blank.
The guide goes on to indicate that every blank should be filled, even if only to indicate that the blank is not applicable, so that those processing the surveys would be able to see that the blank had not merely been overlooked. An Information Circular from the U.S. Department of the Interior, Bureau of Mines, from the same year specified that it used "NA" to indicate that information was "not available" and "NAp" to indicate that a category information was "Not applicable".
In the early years of computer programming, computerized forms that required fields to be filled in could cause problems where the field was one for which no answer would be applicable to certain persons filling out the form. Before programmers became aware of a problem with a particular field, persons filling out that field might fill it in with a term such as this, which the program processing the form would misinterpret as an intent to provide the requested information. For example, if a form contained a field for a middle name, and the person filling out the form put "N/A", the computer might interpret this as "N/A" being the person's middle name; this in turn might result in the person receiving mail from the company that produced the form with "N/A" where a middle name would normally appear.
- Oxford Dictionary of Abbreviations. Oxford University Press. 1998. Retrieved 2010-11-14.
- Barbara H. Foley, English In Action (2003), p. 192.
- Alan C. Kay, J., Metzler Contracting Co. Llc v. Stephens, 774 F.Supp.2d 1073, n. 12 (D. Haw., 2011): "If the contract was a cost-plus-fee contract with no guaranteed maximum, then the arbitrator could plausibly determine that the preliminary budget did not constrain the contract sum. On the other hand, if the contract sum could not exceed the preliminary budget, as amended, then the arbitrator could plausibly determine that the contract did have a guaranteed maximum, despite its express provision that the guaranteed maximum was “N/A.” The former interpretation is consistent with Metzler's contention that “N/A” means “not applicable,” whereas the latter is consistent with the Stephenses' contention that it means “not available,” in that the contract required Metzler to prepare the preliminary budget after the contract was signed".
- Franklin D. Elia, J., Santa Clara Cnty. Dep't of Family & Children's Servs. v. C.K. (Cal. App., 2010): "We are not persuaded by appellants' claim that the January 2008 notice was defective because "N/A" was entered in the space for the tribe or band of the children's maternal great-grandmother Elsie Margaret Hamilton Senna. The record does not establish that the great-grandmother was affiliated with any particular Seneca tribe or band. The abbreviation "N/A" or "N.A." or "NA" can mean "not available" as well as "not applicable". (See Webster's Ninth New Collegiate Dictionary (1990) p. 1380; Prince's Bieber Dictionary of Legal Abbreviations (6th ed. 2009) p. 420; "N/A," http://www.all-acronyms.com/N/A (September 28, 2010)".
- "Not Assessed Definition". Law Insider. Retrieved 2021-10-27.
- Edmund de Schweinitz Brunner, Surveying Your Community: A Handbook of Method for the Rural Church (1925), p. 76.
- U.S. Department of the Interior, Bureau of Mines, Information Circular (1925), p. 42.
- Jim Melton, Alan R. Simon, SQL: 1999: Understanding Relational Language Components (2002), p. 50.