August 23, 2021

RCVGraphis map of vote distribution
NYC Ranked Choice Vote Allocation

New York’s first citywide election using ranked choice voting has now been mapped in detail by the Center for Urban Research (CUR) at The Graduate Center, CUNY. 
The interactive map shows the local patterns of the city’s ranked choice vote (RCV) tallies by election district for the June 2021 primary. The map is the first-of-its-kind that visualizes multi-candidate vote patterns, showing the local round-by-round RCV vote transfers for each mayoral and comptroller candidate.
The Center’s map displays the local vote flow across each RCV round with color-coded diagrams (example at right) linked to each of the city’s 5,600 election districts and 65 State Assembly districts. The charts show visually and with supporting text the votes allocated from each round’s eliminated candidates to remaining candidates. The diagrams are updated instantly for each district as you interact with the map. This reveals the local ranking patterns of voters by neighborhood, and where each candidate benefited from votes from lower-ranked candidates.
“We now have the most detailed look at one of the most momentous elections in New York City history,” said John Mollenkopf, Center for Urban Research director. “This will allow us to explore all the ins and outs of an election that promises to change the tenor of city politics for years to come.”
The vote flow diagrams on the map reveal that in Assembly district 48 covering the Borough Park and Midwood neighborhoods of Brooklyn, almost all of Andrew Yang’s votes were allocated to Eric Adams and almost none to Kathryn Garcia.
In almost all Assembly districts where Maya Wiley did best, most of her ballots were transferred to Kathryn GarciaIn most districts where Adams did well, however, more of Wiley’s votes were allocated to Adams than to Garcia.
The flow diagram for each district also highlights where votes were rendered inactive (were not allocated to any other candidate) in each RCV round. This shows if inactive votes are concentrated by neighborhood, and where each eliminated candidate’s votes were exhausted. 
For example, most of the ballots for Andrew Yang in Assembly district 49 in south Brooklyn and Assembly district 40 in northeast Queens were exhausted after Yang was eliminated in Round 7. His remaining votes were split between Adams and Garcia in those ADs.
The Center’s map is based on the “cast vote record” files provided by the New York City Board of Elections, representing each ballot’s specific rankings. The cast vote record data is anonymous. CUR used the “RCV Tabulator” (RCTab) software developed by the Ranked Choice Voting Resource Center ( to aggregate the individual cast vote ballot records by district. RCTab is used by the NYC Board of Elections to tally the official results. The RCTab software not only incorporates all the RCV rules used by NYC, but is one of the few software packages that can produce election district results based on cast vote record data.
“The Ranked Choice Voting Resource Center is thrilled that our RCTab software could provide the election-district-level results for this first-of-its-kind ranked choice voting results map in New York City,” Chris Hughes, policy director of the Ranked Choice Voting Resource Center, said. “Pairing powerful data analysis like this map with open source software like RCTab ensures that the public gets valuable election information in a trustworthy and transparent way.”
The data display for the RCV map is also possible through the generous support of Mapbox, a mapping and location cloud platform, which hosts the geographic data layers for the map.
This fall, CUR will analyze the RCV vote results in relation to local demographic data and other vote patterns. The Center is partnering with Common Cause New York on this research project.
More maps and analysis of the RCV vote patterns are available via the CUNY Graduate Center’s NYC Election Atlas at and .