How did San Francisco Vote? (update)

Update (July 1, 2016): Tyler’s maps were recently featured in election coverage articles at Curbed SF and the San Francisco Chronicle. Great job, Tyler! — The DSWG

The California Primary was on June 6th, and San Franciscans turned out in… respectable numbers.  Of the 468,238 registered voters in the city, 264,993 or 56.59% cast their ballot either in person or by mail.

One number that made the headline rounds was the 37,198 registered Republicans in San Francisco. The number that wasn’t as publicized was the 18,296 Republicans who actually voted. That’s 49%, a much better turnout than the 14% of voters who registered with no party preference, but not as high as the 66% of registered Democrats who did their civic duty.

Numbers are only meaningful in context.  One of the goals of the Data Science Working Group is to make numbers make sense, to figure out the story behind the data.  But in order to understand the story we need to know what questions to ask.

Data visualizations can help when exploring data as a way to figure out those questions.


Clinton vote


Sanders vote

The choropleths above show the difference in the Sanders and Clinton vote in San Francisco precincts, but creating them led to more questions: what would it look like to “put them on the same axis,” in other words, subtract one from the other?

It just so happens doing that is relatively simple:

Clinton votes - Sanders votes in each precinct

Clinton votes – Sanders votes in each precinct

Now we can see which areas of the city each candidate led.  Having interesting visuals leads to asking questions, which leads to more insights.  The next question? Yet to be asked.  Take a minute to explore for yourself with the tool I wrote to visualize this voting data.

Some more maps for perusal:

Trump voters

Trump voters

Kasich voters

Kasich voters