What Data Set to Use for Our Transit Equity Project?

What demographic data sets will we use to compare against Transit Score to assess equity?

The 2000 Census is currently the only complete data set at the census tract level, so we’re going to start there. Obviously that’s way out of date and we shouldn’t reach any strong conclusions based on it.

I was asked in an earlier thread if ACS (American Community Survey) data was available at the tract level and I answered that it was. I was almost right. ACS is based on annual sampling (as opposed to the complete census that happens every 10 years) but features a longer questionnaire and therefore more data items.

In order to accumulate enough data points for areas as small as a census tract (a census tract has about 8,000 people, give or take several thousand), it takes five years of ACS sampling. ACS will release its first 5-year data set in December 2010, so at the point we would switch over and have much more current data. The 5-year data sets will then be updated annually (kind of a moving average) and that would likely be the preferred data set on an ongoing basis.

And on the mapping front, with the help of a KML file from TriMet, we’ve added the outline of the service district to the map. Our scoring process has finished Clackamas County and has now moved on into Multnomah County.

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