I was thinking about the neighborhood of Harlem in New York City. I read that only 3 percent of the voters in this neighborhood are registered as Republicans and over 80% are registered as Democrats. So, I want to know about how the neighborhood voted in the 2016 presidential election. According to the different precincts that I randomly selected, it appears that Trump got ~2.5% of the vote there. Is that an accurate analysis?
This was actually quite tricky to collate. There is no official list that I could find of electoral precincts within Harlem, and I didn't want to do it manually, so I instead used this shapefile for New York's Community Districts. Manhattan Community Board 10 is roughly the correct boundaries for Harlem. I overlayed the district with this shapefile for New York's precincts, which gave me the list I was after.
After that, it was just a matter of matching up the data with the precinct electoral results courtesy of Open Elections. For a Trump vote, I counted any vote for the Republican or Conservative tickets; for a Clinton vote, any vote for the Democratic, Working Families, or Women's Equality tickets.
Using this definition, Harlem placed a total of 1,270 votes for Trump, and 47,965 for Clinton - equivalent to a two-party advantage of D+95. 1,102 votes were placed for other candidates, so Trump attained 2.52% of the overall vote in the neighborhood. Below is a map showing the two-party advantage on a per-precinct basis.
The most Republican precinct in terms of percentage was 022/71, with 19 votes for Trump compared to 364 for Clinton, a two-party advantage of D+90, while the most Democratic precinct was 020/71, with just 6 votes for Trump compared to 741 for Clinton, a two-party advantage of D+98.