API Technical Discussions

Access Micro-data for Blocks

I'm working on a school project with 2010 Census data.

Currently, we are getting tract-level data using codes from http://api.census.gov/data/2010/sf1/variables.json to get data.

For example, to find the white 65-year old males in a county's tracts, we make the API call:


However, when making the same call at a block level, the file is empty. See:


We assume this is because the 2010 variables we are currently using are pre-aggregated data. It would be infeasible to compile this data for all the blocks.

How do we get access to the micro-data to get results at the block level (ex: white male 65-year-olds per block)?


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  1. Comment
    Community Member

    PCT tables are tract level up; no block data. You will need to use P tables to access block population items.

  2. Comment
    elizabeth.duncan ( Idea Submitter )

    What are P tables? Can you link me to documentation that will specify how to access them?

    Thanks for the help!

  3. Comment
    elizabeth.duncan ( Idea Submitter )

    Sorry for the delay - my team was out on spring break.

    This was super helpful and we will change our code accordingly.

    However, does that mean it is IMPOSSIBLE to get data on age, gender, and race for a block level? Because only variables starting with PCT have that information....

  4. Comment
    ( Moderator )

    Hi Elizabeth,

    Do the P12 selection of tables (as referred to by the community member above here: http://www.census.gov/prod/cen2010/doc/sf1.pdf PAGE:142) not fit your purposes? Those tables contain Sex and Age broken out by Race groups at the block level...

    Just trying to make sure I understand your needs.

  5. Comment
    elizabeth.duncan ( Idea Submitter )

    We just looked at the P only codes - and those span five years (which will work for our project). For example, P012A015 gives white males from 45 to 49 years. We are currently using these codes now, and they are working great! :)

    Just out of curiosity, however, I asked in my comment if it was possible to get a specific age (ex: white males of JUST 45 years). I didn't see any P codes that had only a year age range.

  6. Comment
    ( Moderator )

    There is usually a limit to the amount of granularity you get in the aggregated tables. Will the 5-year swaths suffice though? :)

  7. Comment
    elizabeth.duncan ( Idea Submitter )

    5 year swaths will work perfectly - I just wanted to make sure that I was getting the best possible granularity.

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