Now that the Census Bureau is busy releasing the 2006 ACS data, I thought it would be timely to post a few links on using the ACS data.  It is VERY IMPORTANT to understand that the biggest difference between the 2006 and 2005 ACS is that GROUP QUARTERS population was ADDED in the 2006 sample.   Areas with large Group Quarters population will see the greatest differences between 2006 and 2005 results.  Workers who live in Group Quarters are more likely to walk to work, so you may see shifts in distributions of means of transportation to work in these areas.    The population threshold for reporting 1-year ACS data is still 65,000 persons, based on place of residence.  The 2005 and 2006 ACS standard tabulation include tabulations for PLACE OF WORK called “for workplace geography”.   Also, the “key” to finding tables on “journey to work” is “08”, for example:  B08###, or C08###, or S08##. 

Cynthia Taeuber’s book, “American Community Survey data in Community Planning” (Trafford Publishing, 2006  website:

trafford.com/06-2809 ) is an easy-to-understand document that covers basic information about ACS, but most importantly, understanding sampling error and confidence intervals.  Note:  The Census Bureau is now using  the term “Margin of Error” to reflect sampling error instead of using confidence intervals (the estimate with an upper and lower bound). 

You can order it directly from Trafford.com, which is a “print on demand” publishing house, but I just found it on Amazon.

(priced at $26.37 and listed as “in stock” )

Also, Cynthia’s material completed for Brookings Institute “for journalists”  is on-line at:

http://www.brookings.edu/metro/umi/events/20061115_ACSreferenceguide.pdf

This document on the Census Bureau’s webpage discussing the 2005 ACS is also useful.  

http://www.census.gov/acs/www/UseData/advance_copy_user_guide.pdf

The FHWA page also includes some material on using ACS data, which was developed for earlier releases of ACS, but are still relevant.

http://www.fhwa.dot.gov/planning/census/acs.htm

Because we prepared profiles sheets from the 2005 ACS data, with comparison to Census 2000, we are currently NOT planning to issue NEW profiles using the 2006 data.  We are currently focusing on PLANS for the NEXT CTPP, using the first 3 year accumulation of ACS data (2005, 2006, and 2007), and conducting research on 1) improving workplace imputation for ungeocoded survey responses, and 2) alternative approaches to disclosure avoidance, to avoid the data suppression problems that arose in the CTPP2000. 

If you have ideas for the 3-year CTPP product, especially NEW or DIFFERENT Tables, please let me know!

Elaine Murakami

FHWA Office of Planning

206-220-4460