Category: Data and Methods

Just How Certain is Merkel’s Victory? 96 per cent, give or take

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The Polls Are Noisy Just over five weeks before the Bundestag election, there is much merriment about the current state of play. Support for the Liberals has been consistently below the electoral threshold of  five per cent for months, which implies that Merkel’s coalition would not be able to continue after September. Consequently, everyone is…

Stata Software for Assessing Survey Bias

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BinaryApe / Foter / CC BYIn a recent paper, we derive various multinomial measures of bias in public opinion surveys (e.g. pre-election polls). Put differently, with our methodology, you may calculate a scalar measure of survey bias in multi-party elections. Thanks to Kit Baum over at Boston College, our Stata add-on surveybias.ado is now available…

A Scalar Measure for Bias in (Multi-Party Pre-Election) Surveys

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All surveys deviate from the true distributions of the variables, but some more so than others. This is particularly relevant in the context of election studies, where the true distribution of the vote is revealed on election night. Jocelyn Evans and I present a method for calculating a scalar measure that neatly summarises such bias for multi-party elections. We also present a Stata module that implements our new method.

nlcom and the Delta Method

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The delta method approximates the expectation of some function of a random variable by relying on a (truncated) Taylor series expansion. In plain words, that means that one can use the delta method to calculate confidence intervals and perform hypothesis tests on just about every linear or nonlinear transformation of a vector of parameter estimates. Stata’s procedure nlcom is a particularly versatile and powerful implementation of the delta method. If you can write down the formula of the transformation, nlcom will spit out the result. And that means that you can abuse Stata’s built in procedures to implement your own estimators.

Statistical Songs Roundup

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Today is clearly a day for statistical songs (are there any other days?), so here are some links to get you started. To kick of the stat song roundup, here are some … interesting insights into the culture that is biostatics, complete with some remarkably dreadful audio material. Obviously, youtube has a whole channel devoted…

My Exodus from Google Reader

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Like many fellow information junkies, I was shocked that Google is killing Reader, then realised that I had not used it very regularly  lately. This is partly because I rely a bit more on twitter these days, partly because last year I began using feedly, a Reader frontend that looks good on my various devices…