Estimating Religion from Census Data

[RI]

As an extension of my world religion map and in light of the fundamental flaws in ARDA data, I'm attempting to estimate religious affiliation based on only data from the Census/ACS with an eye on finding an adequate model to project to sub-county areas. The single most useful figure available is ancestry data, to which I've attempted to assign each of ~190 ancestries an approximate religious distribution. In light of the recent Pew results, I've tried to create a model that matches their state-by-state results. I also used their results to identify a possible proxy for the variance in the nonreligious distribution: white, never-married males.

The model I've come up with isn't perfect, but I think it's pretty good so far. Here's a county map for the contiguous US:



Compare to this map based on ARDA data:


I'm aware of a few issues, such as not yet having a great proxy for the Jewish population, but if there are any other glaring issues, let me know. When it's adequate, I'll try making some sub-county maps.

[RI]

Does teal/green represent unaffiliated? If so, I'm surprised at Kittitas County in Washington.

Yeah. I think my method may over estimate the non-religious population in college areas. Here's a census tract map for Washington using this method; as you can see, Kittitas being nonreligious is entirely due to Ellensburg and CWU's influence.





Generally, it seems fairly accurate to me. It might overestimate the nonreligious population near military bases (see Fort Lewis and Naval Station Whidbey).

[RI]

I think the Pullman area may very well be nonreligious, but I don't think it's as nonreligious as my map shows. However, to get Washington to be 32% nonreligious, you need a lot of those types of areas to show up as green.

[RI]

Fascinating! Are non-Christian religions being included?

Yes, but they don't have pluralities outside of a few major cities.

[RI]

Very cool, and it seems more accurate than the ARDA map. How Catholic are you saying Hispanics are? I would have expected places like East Pasco to be darker shades of red.

Also, do you have a color key?

Hispanics in eastern Washington tend to be more LDS than in other places.

The key is standard Atlas shades (>20%/>30%/etc.) with Red being Catholic, Blue being Protestant, Green being Non-religious, and Yellow being Mormon. The grey area in Benton didn't have any people reporting an ancestry.

Yeah, there's noway that non-religious is a plurality in Watauga County.

Yeah, probably not. As I said, college towns are a bit of a problem, but I'd imagine Watauga isn't hyper-Protestant either. It should probably be similar to the shading of Orange County, NC.