Sep 27, 2008
Jens, a long-time reader, tried to re-make the boring data tables used to report poll data. Here is an example from USA Election Polls (left) and his enhanced version (right).
Like Jens, I find most of the tabular presentation of poll data underwhelming. Too much data hiding all the useful information. For example, the pollster and polling date data provide a context for super-serious poll watchers to interpret the data; however, they do not present themselves in a way that actually help readers. Read further for versions that bring out this data much better.
Meanwhile, Jens' revision uses color and ordering to bring out the current state of affairs. The addition of electoral votes allows us to understand the relative weight of each row, countering the weakness of the tabular format, that each row has the same height, implying erroneously that they have the same importance.
There are a number of good web-sites where this type of data is presented in attractive ways.
I have been a fan of Political Arithmetik, which made great use of the pollster and polling date data mentioned above. Those data have been averaged to show the overall trend while the individual poll results are plotted as dots in the background. The polling date data is embedded in the horizontal positions of the dots. Even more impressively, the margins of error are presented. Remarkably, this race has been a statistical tie for all these months, the 95% lower limit never quite making it above the zero level.
Another great site is fivethirtyeight.com. Below, they essentially turned Jen's enhanced table into a map. The legend on the right perhaps represents what they call "East Coast bias"? All of Nathan's graphs are very attractively produced; I just wish he'd put more labels on them (such as the differentials corresponding to shades of red and blue.)
Even better, a cartogram with state area proportional to Electoral votes is updated at Andy Tanenbaum's electoral-vote.com with each day's worth of new polls . (Do try use "next" link past the current chart while there.)
Posted by: bill ricker | Sep 28, 2008 at 11:01 PM
I've been following the daily polls on fivethrityeight as well and I'm glad for their analysis as well.
One thing that could help the tables at the beginning of the article might be the inclusion of sparklines. While that wouldn't give as good of an overall snapshot like the Political Arithmetik chart, it would at least give some much-needed historical context to the numbers with a minimum of added 'ink.'
Posted by: Andy | Sep 29, 2008 at 03:04 PM
The state borders on the lower graph are too thick.
Posted by: Andrew Gelman | Oct 16, 2008 at 10:04 AM