Tomorrow is Election Day here in the States.  The big vote (for President) isn’t until next year, but we have the usual spate of races for local offices as well as a wide range of citizen-initiated referenda on everything from the mundane (bond measures) to the highly divisive (social issues).

As the expected avalanche of survey results washes over me and everybody else (accompanied by a barrage of television advertising, internet electioneering, and attack mailers), I thought I’d share some tips for understanding which poll results to heed, and which to take with the proverbial grain of salt.

My experience in the world of election polling has given me a bit of insight into this topic; I hope these tips help you find your way on your journey through the sea of election polling data.

1. Understand the Methodology

The best way to judge an election poll – indeed, any survey – is to have a good understanding of the study’s methodology.  Unfortunately, reporting on survey methodology is often woefully inadequate, scarcely going beyond a reporting of the margin of error.  However, sometimes one can read between the lines of a story to gain a better understanding of the circumstances under which the poll was conducted, including: timing, data collection mode and survey length.

If the methodology is completely unclear from the article, be a good citizen and email the editor requesting clarification.  The rest of us will thank you!

2. Think Random

Generally speaking, in election surveys, relative to market research surveys, it is particularly important to have sampling methods that give all likely voters as equal as possible an opportunity to be surveyed.  Look for efforts to ensure a representative sample, including:

- surveying voters at different times of day and on different days of the week
- compensating for sampling limitations such as telephone coverage, cell phone coverage, and internet access
- using a “likely voter” screening question, ensuring only those both registered and likely to vote are considered.

Also, be wary of  polls conducted using automated telephone interviews rather than trained interviewers.

3. Evaluate the News Source

As good a data consumer as you are, you cannot realistically check the fine details of methodology on every study.  Therefore, pay attention to the reputation and track record of both the publishing entity.

More reputable organizations tend to higher publishing standards than less reputable ones; they have more to lose if they publish bad reporting.  Put more stock in a study reported by the Washington Post or the Pew Research Center than a study sponsored by a smaller or less reputable newspaper, website, non-profit organization.

In local elections, sometimes the most reputable (though hardly infallible) source is the state or locality’s largest newspaper.  However, look for critical analysis rather than simple reporting of results.

4. Pay Attention to the Sponsor.  Often a group with a vested interest in an election will privately commission a survey to be used for internal strategy; however, if some of the results support their public relations efforts, they will release an (often-misleading) subset of the data in order to influence the electorate.  Sometimes entire carefully-worded polls will be conducted which are meant for public release.  Be very skeptical of any data paid for by a group or persons with an interest in the election’s outcome.

5. Learn from the Experts.  There is a wealth of great content created by smart people who focus on analyzing election data.  Take advantage of their wisdom!  I’m partial to HuffPost Pollster (formerly Pollster.com) – check out my friends Mark Blumenthal (a.k.a. “@MysteryPollster“) and Margie Omero – and Nate Silver’s Five Thirty Eight blog at the New York Times.

These resources are primarily focused on U.S. Elections; there are undoubtedly many more good resources out there both for the U.S. and everywhere else; please suggest others in the comments section below.

I hope these tips are useful to you.  And if you’re in the U.S., don’t forget to vote tomorrow!