Wednesday, June 4, 2014

Who Turns Out?

About six weeks ago, I ran across this story, sort of a typical California pre-election analysis piece. The title of the article (as reprinted in the Petaluma Argus-Courier) made me squint to make sure I was reading it right -- "Bay Area tops state's voter turnout." I started reading, and one paragraph in particular caught my eye, because it mentioned Sonoma. "Poor people from Sonoma are far more likely to cast a ballot than someone living in poverty in Echo Park [Los Angeles]." The article attributed the quote to Paul Mitchell, the vice-president of Political Data Inc.
Paul Mitchell
image available at

High voter turnout, expressed as a percentage, is generally seen as evidence of the legitimacy of a political system, while low turnout can lead to unequal representation among various parts of the population. Low turnout tends to be concentrated amongst the young and the poor, leading to significant under-representation in elections, with the potential to lead to improperly skewed policy. If Paul's right, that's pretty good news for Sonoma County.

So I went and took a look at the election results last night and this morning, to see what the data looks like.  California does a very efficient job of reporting election returns from different counties as they come in; the page is here. The Secretary of State conveniently makes the data downloadable as a CSV (thank-you!).  I pulled it this morning and graphed turnout, expressed as a percentage.  The results are on the right; a PDF of them is here (you'll probably need the resolution of the PDF to see the individual county names labeling the data points). 

I plotted the data on the log of the number of voters in each county, because the massive variance in the number of registered voters (Alpine with 766, Los Angeles with 4,857,424) makes a lin-lin comparison nearly impossible.  I did a power law regression on the data, which fits pretty well; as county size scales, voter turnout appears to decline fairly regularly.  
PDF available at

So, the Bay Area doesn't lead the state in turnout.  That award goes to the northern counties, and those of the Sierra foothills.  Tiny Sierra County turns out more than 60% (Alpine, so small I couldn't even get it on this graph, turns out nearly 70%).  There's a cluster of nine (admittedly, sparsely populated) counties clustered near 40%, all with 50,000 voters or less. Voting's a big deal in a small, perhaps remote community, and it shows.  

A second cluster drew my eye -- on the lower right, seven counties, all with more than 1.4 million citizens.  They are Santa Clara, Alameda, Sacramento, San Bernardino, Riverside, Orange, and San Diego Counties. Between them, they have 6,993,135 registered voters -- two million more voters than Los Angeles County, and a million more voters than the remaining 50 counties combined.  Their turnout is exceptionally low; only two of them managed to clear 20%, Santa Clara and San Diego, and even then, it was by a whisker.  Their location's also interesting; these counties are generally the southern (and to some extent, the eastern) neighbors of the California metropolises that garner an outsized degree of attention, San Francisco and Los Angeles.  

It was the third cluster that really got my attention, though. It's a cluster that's significantly above the trend line.  This group of counties, despite their size, still turn out a relatively high percentage of their voters. From north to south, they are Sonoma, Marin, San Luis Obispo, and Santa Barbara counties.  The number of voters inside these counties is modest. But the number of votes they cast is significant. The four counties were responsible for 219,674 votes on June 3; only Orange, Los Angeles, and San Diego Counties cast more votes than the four put together. The 1,453,951 residents of the quartet cast just 20,000 votes less than the 3.09 million residents of Orange County. 
PDF available at

The parallel between Santa Barbara and SLO, and Marin and SoCo, strikes me as interesting. While it is Paul's point concerning poverty that got my attention, it is the similarities between the "1-2" northern territories of the great coastal cities, and the fact that they are both amongst the most substantial positive outliers (to the extent we consider higher turnout beneficial) on the graph, that holds my attention.  The unusual motivation of their citizens to participate in their governments makes me wonder what other trends in the data patterns for the two sets of counties may coincide.

But that's a question for another day ...