tungwaiyip.info

home

about me

links

Blog

< November 2010 >
SuMoTuWeThFrSa
  1 2 3 4 5 6
7 8 910111213
14151617181920
21222324252627
282930    

past articles »

Click for San Francisco, California Forecast

San Francisco, USA

 

Charting San Francisco Ranked Choice Voting

Last Tuesday, 5 of San Francisco city supervisor's seats are opened for election. San Francisco uses ranked choice voting. Each voter can mark multiple candidate in order of preference. In the initial round, if the top candidate did not get a majority of votes, it goes into instant run-off. The candidates with the fewest number of votes are eliminated. Its votes are transfered to the remaining candidates according to the next preference on each ballot. This process repeats until one candidate obtains a majority of votes among the remaining candidates.

This year 4 out of 5 of the district election has headed for instant run-off. The most crowded field are the 14 candidates competing for district 6 seat and the 21 candidates competing for the district 10 seat. The preliminary election result released (Nov 6) shows the epic battle of over 10 rounds of instant run-off before a candidate wins. To visualize how the process play out, I have charted the election data below.

The colored lines connects the candidates in each round. A circle marks the front-runner and a cross marks the candidates eliminated. Each time a candidate is eliminated, those votes are transfered to the remaining candidates. This "lift" up the line of the next round. In district 6 we can see that the relative position of the top 3 candidate are unchanged through out the process, with Jane Kim leading all the way. District 10 is more dramatic, with the front-runner status pass around the top 4 candidates. We see that Marlene Tran has propelled to the front-runner in round 15 after Teresa Duque was eliminated in round 14 (marked by the red cross). Interestingly no one but Tran has received much of Duque's vote. In a similar fashion, Dewitt Lacy's elimination lift up Maria Cohen. And Steve Moss' votes have passed mainly to Tony Kelly. Finally Lynette Sweet's vote goes mostly to Maria Cohen, making her the winner in under the preliminary result.

The election department is expected to release the final result in a few weeks. It will possibly change the result in a close race such as district 2. I will updated the chart once the data is available.

I have also made a first pass chart that I find not as informative.

To view the election chart it requires a web standard compliant browser with SVG support, e.g. Firefox, Chrome, Safari or Opera. IE 8 or below is not supported. Thank you.

2010.11.08 [] - comments

 

 

blog comments powered by Disqus

past articles »

 

BBC News

 

George Floyd death: Lawyer calls it 'premeditated murder' (31 May 2020)

 

SpaceX Nasa Mission: Astronauts on historic mission enter space station (31 May 2020)

 

Coronavirus changes how doctors deal with death (31 May 2020)

 

Coronavirus: Brazil now fourth-highest nation in Covid-19 deaths (31 May 2020)

 

Christo: Bulgarian-born artist who famously wrapped landmarks dies at 84 (31 May 2020)

 

Coronavirus: Belgian Prince Joachim apologises for Spanish lockdown party (31 May 2020)

 

Mining firm Rio Tinto sorry for destroying Aboriginal caves (31 May 2020)

 

Glimmer of hope for world's rarest primate (31 May 2020)

 

Coronavirus: Queen seen in public for first time since lockdown, riding pony (31 May 2020)

 

#JusticeForUwa trends in Nigeria after student murdered in church (31 May 2020)

more »

 

SF Gate

 

Ship traffic, June 1 (30 May 2020)

 

Ship traffic, May 31 (30 May 2020)

 

Popular Costco perk is coming back (29 May 2020)

 

Ship traffic, May 30 (29 May 2020)

 

Ship traffic, May 29 (28 May 2020)

 

Ship traffic, May 28 (27 May 2020)

more »


Site feed Updated: 2020-May-31 18:00