Half of the observations listed as "not available" for question that asked for residence 5 years ago in 1980, 1990 census volumes

I am looking at the migration information on census data that asks where the person lived five years ago looking at 1970, 1980, and 1990 census data using the variable MIGPLAC5. I am specifically interested in migration at the state level. This works well for 1970, but about half of the observations for MIGPLAC5 are categorized as “Not available” in the 1980, 1990. The “not available” category seems to be distinct from “missing” data. Is there any reason why half of the observations are listed as “not available” after 1970?

Thank you!

As noted on the MIGPLAC5 universe tab, MIGPLAC5 is only available for 50% of cases in 1980. Migration, place of work, and travel time to work items were only coded on half of the questionnaires (see page 18 of this 1980 Census report) as these were hand coded from free text responses. Guidance on using the migration/place of work/travel time variables in 1980 is available on the MIGPLAC5 comparability tab as well as the MIGSAMP description tab.

Hello Krari,

Thank you so much for your assistance. It was very helpful.

Hello, I am using migplac5 from the 1980 data and I wish to clarify the statement in the variable’s comparability section which reads, “For correct absolute numbers, users should select cases coded as 2 in MIGSAMP and multiply by 2 as well as by PERWT.” Does this statement imply anything more than multiplying the weight (PERWT) variable by 2? For instance in STATA,
replace perwt= 2*perwt if migsamp==2

If it does imply something beyond multiplying the person weight by 2, would you please provide one example of an adjustment using an existing variable in the dataset?

Thank you,

Jennifer Hurst

Your interpretation is correct. Note that you only need to multiply PERWT by 2 to get totals, whereas this step is not necessary to get means or proportions. I would also recommend creating a new variable instead of modifying PERWT directly because this adjustment is only appropriate for a limited set of variables.