zlacker

> The consequence is that performing any analysis with an assumption that ZIP codes are polygons is bound to be error-prone.

Yeah, but any analysis you're likely to perform is approximate enough that the fact that ZIP codes aren't polygons is basically a rounding error.

Plus, it's a lot easier to get ZIP codes, and they're more reliably correct, so you might still get better results, than you would going with another indicator that is either (a) less reliable or (b) less available.

>>mcphag+(OP)
They aren’t reliable correct actually. The boundaries that the Census publishes are called Zip Code Tabulation Areas which are approximations of zip codes and include overlaps.

>>mattfo+mf
ZCTA5 roughly corresponds to the area of a 5 digit zip code. Problem is there are large areas of the west that don’t have permanent residents and no mail delivery. Plus they change over time.