Important methodological notes

Updated: 2018.09.16

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We suggest using the "Distance" version of the scale, as it was derived from a simpler procedure and did not appear to suffer substantial limitations relative to the "Time" version. This is further explained and we make this same recommendation in the paper (preprint).
The data file (linked from the home page) contains three fields:
1. FIPS: Census tract identifer. This is a commonly used identifier that should be 11 (eleven) characters in length for every record. Note that if you open the data file in Excel and save it, Excel is very likely to chop off a leading zero, resulting in some identifiers being only 10 (ten) characters. This could cause trouble when trying to link this data with other data sets. Don't use Excel. Ever. For anything.
2. IsoDist: "Distance" version of the geographic isolation scale, as described in the paper (preprint) (δ = 0.86).
3. IsoTime: "Time" version of the geographic isolation scale, as described in the paper (preprint) (δ = 0.89).
The published paper (preprint) contains quantitative descriptions of the geographic isolation measure that are not likely to align perfectly with those you generate yourself. The reason for this is that, while we used the exact same data in the paper, the data set was subsetted to include only Census tract records for which all rural/isolation measures were not missing. This resulted in the exclusion of some tracts from the analysis completed in the paper. Descriptive statistics should only be subtly different, however.