When during the year is the ACS administered?

I’d like to calculate approximate age in quarters at time of survey. For some ACS extracts, quarter of birth is available. But, to calculate approximate age in quarters, I would need to know the quarter when the survey is administered. Is that public knowledge? Is the ACS typically administered in the first quarter of the year?

Thanks so much for all of your help. I really appreciate it!

The ACS is a monthly rolling sample, which is briefly described on the sample designs page. This means that not all persons in the sample responded at the same time. Unfortunately, the PUMS files released by the Census Bureau do not include a variable indicating when the respondent answered the ACS questions.

I have a similar question. About when did people respond to the 1940-2000 census long form (so that we know the rough time period on which the respondent’s answer (e.g. age) were based)? Is there something like a time frame such as the 19xx census long form was administered between month A and month B? I tried to find information online but have not found any information source that covers the full range from 1940 to 2000 and pertains to the long-form respondents.

The reference period for many (but not all) Census questions was Census Day, and this differed from decade to decade. The Census Bureau has an FAQ page on the timing of Census Day. You can see exactly how the question was asked in each year (for most years) on the questionnaire text page for AGE. For more details, I would advise looking at the original Census instructions and questionnaire forms available on the Census Bureau History website.

In some years (including 2000 and 2010) respondents were instructed to give the person’s age on April 1. In 1990 it was the person’s age at their last birthday. Other years collected the month and year of birth, but this is not available in the public use microdata for most years. I’ll also point you to this previous forum post on BIRTHQTR.