Dear NHGIS -
I am working with your 1980 decennial census place-level data. However, it does not appear that suppression flags were digitized by NHGIS. Is this correct or am I missing something?
Per the original Census documentation, each STF3 line should be accompanied by a series of 0-1 suppression flags which identify whether or not a cell reflects real suppressed data. The 1980 Census sets suppressed values to “0” so without the suppression flag it is difficult to know if, say, a certain place’s aggregate family income was truly 0 or that it was just suppressed and the cell was set to 0.
Thank you for you time and all of your hard work.
We updated the NHGIS data access system to provide suppression flags in data extracts in October, 2022. Thus, we now provide the suppression flags for datasets that provide them. In the 1980 STF3 extracts, the suppression flag column names are typically SUPFLG01, SUPFLG02…
If you are using 1980 data downloaded prior to October 2022, then you will not find the suppression flags in the data extract. Any extract created after October 2022 should include the suppression flags. In order to interpret the suppression flags, you will have to use the technical documentation. For 1980 STF3, you will find details about suppression flags on pages 23-27.
Dave Van Riper
I bet I’m just using data from an older download.
I appreciate all of your help.