Q. Do I have to state how old I am on my 2010 Census form or can I say “over 65”?

The 2010 Census form asks for everyone’s age and date of birth; the Census Bureau wants both because people sometimes give their ages incorrectly and the birth date offers a way to double-check the information. If a census form is incomplete, census-takers may try to phone or visit the household to obtain the additional information. If they cannot get the missing information that way, they may impute it — that is, apply statistical techniques to make a sophisticated guess based on characteristics of similar people.

Information given to the Census Bureau is confidential under federal law. Data are used only for statistical purposes, and any information about an individual is not allowed to be released for 72 years. Please note that the Census Bureau does not ask for information such as Social Security numbers, credit card numbers or personal financial information.

Why does the Census Bureau want to know how old you are? There are a number of federal programs that use data about different age groups to allocate funding or services. They include programs for children, women of child-bearing age, and older adults. According to a Census Bureau publication, “the Department of Education uses census age data in its formula for allotment to states. Under the Voting Rights Act, data on the voting-age population are required for legislative redistricting. The U.S. Department of Veterans Affairs uses age to develop its mandated state projections on the need for hospitals, nursing homes, cemeteries, domiciliary services, and other benefits for veterans.”

D’Vera Cohn, senior writer, Pew Social & Demographic Trends project