# What scenario would cause an NA (missing data) entry rather than a zero? NA specifically means that the endpoint cannot apply to a scenario and leaving a 0 would skew association results - for example, for prostate cancer females are NA, or for open-angle glaucoma cases the less-specific "other glaucomas" entries are NA. In some endpoints we have done stricter delimitation of controls, meaning that we remove controls based on certain criteria. For example, in \_EXALLC endpoints, all cancers have been removed from the controls, and in \_EXMORE endpoints a stricter control cut off has been used. These individuals will appear NA in the data. NA entries are perfectly acceptable and will be skipped in analyses without adding any spurious controls, especially if you're working with more strictly delimited data. However, if you're confident that your data should not have any NA entries and a substantial number are present, we suggest contacting . --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.finngen.fi/faq/about-endpoints/what-scenario-would-cause-an-na-missing-data-entry-rather-than-a-zero.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.