[CTPP] Question about PUMS data and Geography

[Patty Becker]

Martin,

The 1% and 5% don't exactly refer to geography. They refer to the 
sampling fraction; the proportion of the total resondents who are 
included in the PUMS files.

PUMS geography is based on PUMAs (Public Use Microdata Sample areas) 
for the 5% files; these have to be at least 100,000 population.  The 
1% file uses super-PUMAs, which have to be at least 250,000 in 
population size. Your state data center should be able to tell you 
what the PUMAs are for your state or area; they're also included in 
the 2000 census PUMS documentation.

Hope this helps.

Patty Becker



At 03:37 PM 3/25/2009, you wrote:
>Hello,
>
>I am looking to create some commute flow maps and I think I remember
>someone mentioning (between all the please remove me from this list
>e-mails) that flow maps can be created by using ACS data and the PUMS
>geography.  I was at the Census site trying to download the PUMS
>geography files and found that there were two types 1% and 5%.  Does
>anyone know which geography file I should use?  The 1% or the 5%?
>Thanks in advance,
>
>Martin Catala
>GIS Manager
>CUTR
>
>_______________________________________________
>ctpp-news mailing list
>ctpp-news at chrispy.net
>http://www.chrispy.net/mailman/listinfo/ctpp-news

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Patricia C. (Patty) Becker         248/354-6520
APB Associates/SEMCC       FAX 248/354-6645
28300 Franklin Road                 Home 248/355-2428
Southfield, MI  48034                     pbecker at umich.edu 
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