Block group crosswalk (1990->2010 and 2000->2010)

Hello, I am working on obtaining the median household income for the years 1990 and 2000, using block group data as defined by the 2010 census geography. I initially planned to collect median household income data from 1990 and 2000, and then apply crosswalks from the 1990 and 2000 block groups to the 2010 definitions. However, I discovered that while block-level crosswalks are available, there are no corresponding crosswalks for block groups. Could you suggest how I might address this issue, or do you know if such crosswalks are available? I’ve searched extensively but haven’t found any solutions. One method I was thinking of is to use a block group shapefile and perform the spatial join. Use the overlapped area as a weight to calculate the median income at 2010geography. However, I am not sure if this makes sense.

Thank you!

To analyze data at the block group level, it can initially seem intuitive to collect input data from multiple years at the block group level. But in fact, as discussed fully on the NHGIS crosswalks page, that’s not necessary, and to generate a time series of data for one year’s block groups, it’s generally more accurate to start with data from the smallest possible units. The smallest geographic areas for which the Census Bureau published 1990 and 2000 long-form census data (including data on household income) are block group parts. For this reason, NHGIS provides crosswalks from 1990 and 2000 block group parts (and not from 1990 and 2000 block groups). This section describes how you can use NHGIS to obtain data for 1990 and 2000 block group parts. You could then link that data to the NHGIS crosswalks to generate data for 2010 block groups.

Another issue is that NHGIS crosswalks are designed to support the standardization of count data, such as the number of households in block groups. See this forum post for guidance on how to handle a non-count statistic like median household income.

This is a huge help. Thank you so much. I will try in that way. Thanks!