There may be a tendency for the following kinds of persons to report erroneously that they served on active duty in the Armed Forces: (a) persons who served in the National Guard or Military Reserves but were never called to duty; (b) civilian employees or volunteers for the USO, Red Cross, or the Department of Defense (or its predecessors, the Department of War and the Department of the Navy); and (c) employees of the Merchant Marine or Public Health Service.

Beginning in 2006, the population in group quarters (GQ) is included in the ACS. Some types of GQ populations may have period of military service and veteran status distributions that are different from the household population. The inclusion of the GQ population could therefore have a noticeable impact on the period of service and veteran status distributions. This is particularly true for areas with a substantial GQ population.

There may be a tendency for people to mark the most recent period in which they served or the period in which they began their service, but not all periods in which they served.

There may be a tendency for people to erroneously report having a 0 percent rating when they have no service-connected disability rating at all.

Current U.S. service members may not be included in every survey, since each survey has its own “residence rule” and “universe”. Surveys using a “current residence” concept will only cover people currently residing in the U.S. Surveys using a “usual residence” concept covers people at the place where a person lives and sleeps most of the time. This place is not necessarily the same as the person's voting residence or legal residence. Armed Forces members currently deployed are typically not counted under either of these rules. The universe of a survey refers to who is sampled for interview. For more on residence concepts by survey, see Frequently Asked Questions.

The American Community Survey (ACS) collects information on current members of the military, but only if he or she has been living at the sampled housing unit for more than two months. If anyone listed on the household roster is away from the sample unit for more than two months, including someone in the military, he or she should not be included on the form.

The Decennial Census collects information on current members of the military, who receive a census form at their military installation or on a military ship. Federally affiliated military and civilians (and their dependents living with them), who are living outside the United States, are counted in the census. For more information, see Census 2010 Residence Rule and Residence Situations.

While the Current Population Survey (CPS) completely excludes military personnel from being interviewed for the main questionnaire, the CPS Annual Social and Economic Supplement (ASEC) sample universe includes military personnel who live in households with at least one other civilian adult. In addition, the August 2008 CPS Migration Supplement also collected limited information on Armed Forces members deployed in the last year.

The universe for theSurvey of Program Participation (SIPP) includes all military personnel residing in the United States, except for people living in institutions and military barracks or households for which ALL adults are currently active duty. SIPP does not interview original sample members if they move outside the United States, become members of the military living in barracks, or become institutionalized (e.g., nursing home residents, prison inmates).

There are a number of sources of data for military families and dependents, but identification of these families varies by survey. The 2000 and 2010 Censuses of the Island Areas include questions on military dependents. The August 2008 CPS Migration Supplement also had a question on whether a person living abroad was a dependent of a member of the U.S. Armed Forces. On the CPS main questionnaire, civilian members of military families can be identified by military personnel being included on the household roster, even if the Armed Services member is not interviewed. Civilian members of military families can similarly be identified on the SIPP survey. On the ACS, identification is limited to civilians living in the same household as an active duty person, and everyone has lived there for at least two months.