“Probabilizing” uncertainty in the Brazilian Presidential Election

[This article was first published on Daniel MarcelinoDaniel Marcelino » R, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

The following figure shows the probability distributions of vote intentions for the main candidates after distributing the stock of undecided voters. As Marina (PSB) is getting back to her track, a question that comes to light is whether Dilma will get more votes than the sum of the others, and what is the probability that she will take it all without a runoff.

Based on the latest polls and simulations (100k) her chances of avoiding a runoff are not that great. There is a 98% chance of seeing a runoff between Dilma and Marina as indicated in the bottom line in graph below. However, if she gains this (most likely) proportion of the undecided voters and “steal” a few more from the other candidates, then that will increase her probability of winning even in the first round.

density

To make it more concrete, in other to avoid a runoff with Marina, Dilma needs to hold a plurality of the late deciders (which is theoretically likely as the undecideds tend to preserve the status quo) and soak up around 3% from the other candidates. Not much but it would end up being a 50/50 chance then.

difference

To leave a comment for the author, please follow the link and comment on their blog: Daniel MarcelinoDaniel Marcelino » R.

R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)