A case of poor scaling in the choropleth property tax values

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I don’t know if the Tax Foundation means to be in the “fibbing with maps” category, but I have some problems with the data presentation that goes along with their new interactive tool where you can go figure out how your county stands up in terms of median property tax. I guess they aren’t really fibbing: more like just wasting our time with a map that doesn’t tell us anything new about property tax burdens.

I can’t figure out where this map originally came from, but I borrowed from the Tax Prof (who deserves a HT). But it has the Tax Foundation logo on it, so I assume they had a hand in making it. Pretty though it is, it’s not helpful.

Here goes:


You can see from the map that the scale on the property tax is exhausted at over $2000 year for median home values. Now, if you look at that, we can see that both Los Angeles County, where my beloved LA is, and Polk County, home of Des Moines, the capital of Iowa, are both dark blue, which means the median is above $2K a year. I’m guessing LA’s median property value is a wooncy bit higher than what we find in Des Moines, so let’s see how much got collapsed into that highest strata by looking at the interactive county tool, where the interesting stories come through.

In the tables, you get the tax paid as a percentage of median home value, a normalized figure–which is what should be mapped thematically if the Tax Foundation wants to tell us something interesting specifically about taxes, rather than home values. As it is, we’re probably getting roughly the same map here, particularly for the coasts, as we would if we just mapped median home values. Or population density. It’s better to separate the effects in a choropleth presentation if you have multiple things going on.

Voila Capture5

So Los Angeles ostensibly looks bad when you look at the tax ranking. It’s 10th in the country. And OMG it’s dark blue! But then when you look at the tax normalized by median home value, the state falls to 37th–the bottom half.

The normalization by median income doesn’t make that much sense, either, unless this is median income of homeowners. It’s likely in places like Los Angeles that some property tax is passed along to renters, but it’s probably not fully passed along, so using the median for the whole population, rather than just the median for the population of homeowners, is a bit misleading there. It’s hard to know what that story is, and it likely changes from period to period as rentals relative to demographics change.

Just to close the loop, let’s look at Des Moines.

Voila Capture6

Los Angelenos and Des Moines residents are paying at the median about the same raw amounts. Yes, there is some difference, but in 2009, it’s about $2,900 for the median Los Angeleno and about $2,400 for the median Polk County resident.

Well, then. What have we got?

We have the median resident of Des Moines paying a little over 1 percent of their home value in tax, while the Los Angeleno pays at the median about 0.61 percent. Los Angeles (and other places in California) are way towards the bottom: 655 out of 790 counties and 37th out of 50 in state ranking on taxes.

Proposition 13, at work. Untaxed wealth in your home value that will continue to grow over time for those who hang on to property due to the weird rules governing assessments under 13.

2 thoughts on “A case of poor scaling in the choropleth property tax values

  1. I guess that all depends on to what purpose you’re giving the numbers. If you’re thinking about it in terms of “fairness” or as “thing potential property buyers should include in their decision,” then yes, we should be emphasizing rates. On the other hand, if you’re thinking about it as an issue of “how much revenue does the property tax bring in” (and by extension, “how many public services can the locality afford”) then the current graph is on the right track (though it should probably be mean or $/capita, not median). Another way to think about it is suppose Loserville has property values of $1 and a rate of 100% that’s a high rate but trivial revenues and the county is going to go bankrupt. On the other hand, if Gnarleytopia has property values of $1 billion and a rate of 0.2% that’s a low rate but plenty of money to the county coffers. (You’d probably want to allow for that high value areas are more expensive to govern since state employees will face higher cost of living, but this should only be a partial adjustment not 1:1 as implied by using the rate).

    Also, on prop 13, one thing I never understood is why we had a bubble in California when prop 13 effectively acts as a transaction tax. That is, if you and I each have houses currently valued at $500K but assessed at only $50K, it would cost us each $4,500 per year in perpetuity for us to trade houses.

  2. Eh, I’m sticking to my guns. If you want tax revenues or tax bases, use total raw numbers by all means. There’s an example where you would want to map multiple effects (housing stock, value, rates). But don’t use median payments then, and probably not revenue per capita, either. Loserville has $2,500 per capita, but it as 2 residents. Gnarleyville has $2500 per resident, and it’s got two million residents.

    Many people who should know tell me we didn’t have a bubble in California. I do not understand this.

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