Nov 132016
 

The one and only Philip Schrodt has written what I think is the perfect seven-take-home-messages rant on that election and it’s likely outcomes. Skip all the self-flagellation/yes-but posts and read this instead:

Then again, there is one thing that does not get enough coverage in there, and that is the whole polling/prediction disaster. So you should read this, too:

There. Your Sunday sorted out.

Jul 102013
 
Used Punchcard
BinaryApe / Foter / CC BY

In 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 from Statistical Software Components (SSC).  The add-on takes as its argument the name of a categorical variable and said variable’s true distribution in the population. For what it’s worth, the program tries to be smart: surveybias vote, popvalues(900000 1200000 1800000), surveybias vote, popvalues(0.2307692 0.3076923 0.4615385), and surveybias vote, popvalues(23.07692 30.76923 46.15385) should all give the same result.

If you don’t have access to the raw data but want to assess survey bias evident in published figures, there is surveybiasi, an “immediate” command that lets you do stuff like this:  surveybiasi , popvalues(30 40 30) samplevalues(40 40 20) n(1000). Again, you may specify absolute values, relative frequencies, or percentages.

If you want to go ahead and measure survey bias, install surveybias.ado and surveybiasi.ado on your computer by typing ssc install surveybias in your net-aware copy of Stata. And if you use and like our software, please cite our forthcoming Political Analysis paper on the New Multinomial Accuracy Measure for Polling Bias.

Update April 2014: New version 1.1 available