Blog Archives

Brazilian Presidential Election

September 25, 2014
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Brazilian Presidential Election

Three major polling houses published their polls this week: MDA, Ibope, and Vox Populi. The following numbers incorporate these data. With current data, a runoff between Dilma and Marina seems to be inevitable (.87), though its certainty has decreased from the previous week as the following chart indicates. How to understand the following plots: The … Read More...

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Brazilian Presidential Election

September 20, 2014
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Brazilian Presidential Election

TweetFor those who follow this tale, the chart below shows the hitherto of vote intentions among the viable candidates as reported in various polls. Data collected over 2012 were simply disregarded and those from 2013 enter in the model as prior values (covariance) for the 2014 estimates. The big dots at the end of the … Read More...

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Yep. He made it; country voted No.

September 19, 2014
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Yep. He made it; country voted No.

Tweet Yesterday, more Scots than ever since universal suffrage was introduced cast a ballot on the matter of independence. The turnout was itself phenomenal and that implicating a series of questions for the government authorities and citizens, but for the time being the sole question was: would this benefit one side or the other? The … Read More...

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Bayes says “don’t worry” about Scotland’s Referendum

September 17, 2014
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Bayes says “don’t worry” about Scotland’s Referendum

Just few hours before Scots head to the polls, there is not an overwhelming advantage of the anti-independence vote. Actually, the margin is shorter than last time I looked at it, but despite such a growing trend in favor of the "Yes" campaign in the last weeks, the "NO" side has an edge still. To … Read More...

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“Probabilizing” uncertainty in the Brazilian Presidential Election

September 11, 2014
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“Probabilizing” uncertainty in the Brazilian Presidential Election

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

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Brazilian Presidential Election

September 9, 2014
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Brazilian Presidential Election

Today’s prediction to include the latest poll by MDA/CNT. The results seem quite stable now, but I Dilma tends to lift few points towards the end of the campaign as the swing voters are more likely to go with the incumbent if they remain uncertain about an alternative. R> summary(mcmc2014) forecast class object: MCMC: 1000

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Brazilian Presidential Election

September 3, 2014
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Brazilian Presidential Election

I hope to have finished the major load on my forecasting model algorithm. I also conclude this project with a new set of clear graphs, although, I still feel working on the colors and scales. I’ve received a few emails asking for more details on the simulations and to make the code available, which is

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Forecasts After Marina’s Turbulence

August 30, 2014
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Forecasts After Marina’s Turbulence

It’s more difficult than ever to tell who is going to continue in the runoff after the October 5th. After Marina’s campaign mate’s death, a big chunk of the electorate have been persuaded towards the alternative between PT and PSDB. The values I used to start the chains, my initial beliefs, were that Dilma would

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What are the Odds of an Independent Scotland?

August 18, 2014
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What are the Odds of an Independent Scotland?

“For things to remain the same, everything must change.” (Gattopardo by Giuseppe Tomasi di Lampedusa) In less than a month, Scots will decide if they want Scotland tied or apart of UK. Over the last days, I’ve noticed a variety of projections in the British press about this, but I decided to give it a

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Discontinuity Bayesian Forecasting

July 16, 2014
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Discontinuity Bayesian Forecasting

I’m finalizing a paper presentation for the ABCP meeting, where I explore poor polling forecast in local elections in Brazil. I drew upon the Jackman (2005)’s paper “Pooling the Polls” to explore a bit about “house effects” in the Brazilian context. However, during the analysis I found myself extending his original model to fit the

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