Connecticut Primary Polls: No Easy Task

For all the attention paid lately to the Connecticut’s upcoming Democratic primary election between Senator Joseph Lieberman and challenger Ned Lamont, public polls on the race remain few and far between.  That scarcity may owe something to the huge challenge of selecting "likely voters" for a rare summer primary in Connecticut where turnout is largely unknown.   This is the sort of race that gives pollsters nightmares. 

Contested statewide primaries in Connecticut are relatively rare, as party nominees are typically chosen by state party conventions.  Another twist, the Stamford Advocate explains, comes from the recent move of Connecticut’s primary from September to August.   The most recent "hotly contested" primary, at least according to the Advocate, was a September 1994 primary in which 26% of Connecticut’s registered Democrats cast ballots.  There is no recent contested August primary, though Genghis Conn’s compilation of past turnout statistics on the Connecticut Local Politics blog argues that the date alone may not make much difference. 

The likely turnout on August 8 is anyone’s guess at this point, but to try to understand the challenge facing the pollsters, consider a few numbers: 

Connecticut has a voter-eligible population of roughly 2.4 million.  The Connecticut Secretary of State reports 1.95 million active registered voters as of last year, of whom 653,055 were registered as Democrats.    Just as a benchmark, consider that if 25% of registered Democrats cast a ballot on August 8, that level of turnout would amount to roughly 7% of the voter eligible population and roughly 8% of all registered voters. 

Now consider the polls released so far.  I am aware of three public pollsters that have released Connecticut results in the last few months: 

• Quinnipiac University — Their most recent poll, taken between May 31 and June 6, sampled 2,114 "registered voters," of whom 751 (36%) were registered Democrats and 465 (22%) were identified as "likely Democratic primary voters."   Although the Qunnipiac release does not specify how they sampled voters for this poll, they typically use a random digit dialing (RDD) methodology, which would require asking respondents how they are registered. 

• Rasmussen Reports – Rasmussen conducted a one-night automated telephone poll on June 12 among just 212 respondents identified as "likely voters" for the August 8 Democratic primary.  The respondents appear to be a subgroup of survey of 800 "likely" general election voters surveyed by Rasmussen the same night.  So Rasmussen’s most recent primary sample was 27% of its general election sample.  Consider that a 25% turnout among Connecticut’s registered Democrats would represent roughly 11% of the 1.4 million ballot’s cast in the last off year elections in 2002.

• SurveyUSA – Although SurveyUSA has not yet fielded a poll that asks the primary vote question, their 50-state tracking polls provide results for Joe Lieberman’s job rating among "Democrats."  Their most recent survey of 600 adults in Connecticut was fielded from June 9 to June 11.  The subgroup of Democrats (presumably based on a party identification rather than a question about party registration) was 42% of the sample, or roughly 250 respondents. 

What should be clear from the above is that all of the samples are small and those that report on "likely voters," appear to select and define them differently.  Neither Quinnipiac nor Rasmussen explains how they identify "likely voters" (although the methods they described in October 2004 are probably close).  And all of these surveys are a bit dated, at least for the moment, as much has transpired in the Lieberman-Lamont race over the last three or four weeks. 

The one thing we do know with some confidence, thanks to the Quinnipiac poll, is that the assumptions the pollster makes about turnout matter a great deal to the results.  Or at least they did in early June, when Quinnipiac had Lieberman leading by 25 percentage points (57% to 32%) among all Democrats, but by only 15 points (55% to 40%) among the smaller subgroup of "likely voters."

Presumably, we will see more polls released in Connecticut over the next four weeks.  Hopefully, the pollsters will tell us a bit more about how they select "likely voters" and about how those likely voters compare to all registered Democrats in their samples. 

P.S.   Charles Franklin’s charting and analysis of the Connecticut surveys got me thinking about the challenge of polling in this race.  His analysis is well worth reading, as always, but keep in mind that the results in his charts are for all Democrats, not "likely voters."