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Variances in Census Block data for two files

Angie
over 7 years ago

Hello and Happy Holidays!

I am using the new 2015 5-Year Data set to update numbers using the Income, Minority and Language ACS Files. When I ran the income numbers for Essex County Massachusetts Census Blocks, I used two data sources: "household income in the past 12 months (B19001)" and "Median Household Income in the last 12 months (B19013). Unfortunately B19013 is missing some Census Blocks (26 to be specific). 6 of those Census Blocks are missing from our specific region. Has anyone run across this in their work? We have a small region, so I have to run the numbers by Census Blocks to get at the specific info we're looking for.

Thanks!

Angie

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  • over 7 years ago
    Hi Angie,
    These missing block groups may be related to the Census Bureau's new rules for suppressing median income and earnings estimates in cases where the margin of error is larger than the estimate. "Beginning in data year 2015, a new methodology was applied to the 5-year dollar-based medians and quintile limits that suppresses the table for the geographic area if the margin of error is larger than the estimate itself. "

    Table B19013 is one of the tables affected by their new methods:
    www.census.gov/.../2016-01.html
  • over 7 years ago in reply to Mark Mather
    Thanks Mark! It's curious that there would be such a high margin of error. Do you have any insight into that?
  • over 7 years ago in reply to Angie
    MOEs are almost entirely driven by the number of cases - interviews - in the group. Census blocks, depending on how many housing units they have, may have 1 or NO interviews in a 5 year period. Where there are few cases, MOEs are sky-high. The ACS really is simply not reliable at the census block level for anything; the only point of releasing block data is to make possible custom geographic aggregations. Even block groups, or in some cases tracts, have very high MOEs.
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  • over 7 years ago in reply to Angie
    MOEs are almost entirely driven by the number of cases - interviews - in the group. Census blocks, depending on how many housing units they have, may have 1 or NO interviews in a 5 year period. Where there are few cases, MOEs are sky-high. The ACS really is simply not reliable at the census block level for anything; the only point of releasing block data is to make possible custom geographic aggregations. Even block groups, or in some cases tracts, have very high MOEs.
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