Why are some basic monthly samples pre-selected?

#1

After selecting ASEC and a couple of other Suppliments, I find that a selection of 79 Basic Monthly files have been added to my sample: the most recent 12 months. all of the October samples, and an oddly irregular selection of June samples. Why are any of these samples added? And why these samples, amd not some other subset of Monthly samples?

#2

This is a follow-on, not an answer. Along with ASEC, I selected three supplimental studies for my sample: Education, Marriage and Fertility, and Voting. So I do ot understand why I see the Education Suppliment under Person variables, but the M & S and Voting suppliments nowhere.

But I do see several suppliments I did not select, Food Security under Household, and Displaced Worker, Job Tenure, and Food Security under individual.

  1. Why are some of the Suppliments I selected not shown?

  2. Why are some of the Suppliments I did not select (but not others) shown?

#3

I understand the confusion here. The reasoning for which samples are selected by default in IPUMS CPS is driven by the reality that only variables that are available in selected samples show up in the select variables drop-down menus. For example, if only basic monthly samples are selected (i.e. no ASEC samples), then the ASEC variables will not show up in the select variables drop-down menus. This being the case, we have selected a number of default samples so that users can see the full range of variables potentially available across all samples in IPUMS CPS. Of course, if you know specifically what samples you’d like to use then you can simple de-select the ‘All Default Samples’ button on the Select Samples page.