When a pollster or media outlet reports multiple horserace numbers RealClearPolitics uses "Registered Voter" results over "Adults" and "Likely Voters" numbers over "Registered Voter" results in the RCP Poll Averages.
The Gallup organization has taken the unusual step in its Gallup Daily Tracking Poll of releasing two sets of "Likely Voters" results.
Likely Voter EstimatesObama's current advantage is slightly less when estimating the preferences of likely voters, which Gallup will begin reporting on a regular basis between now and the election. Gallup is providing two likely voter estimates to take into account different turnout scenarios.
The first likely voter model is based on Gallup's traditional likely voter assumptions, which determine respondents' likelihood to vote based on how they answer questions about their current voting intention and past voting behavior. According to this model, Obama's advantage over McCain is 50% to 46% in Oct. 9-11 tracking data.
The second likely voter estimate is a variation on the traditional model, but is only based on respondents' current voting intention. This model would take into account increased voter registration this year and possibly higher turnout among groups that are traditionally less likely to vote, such as young adults and racial minorities (Gallup will continue to monitor and report on turnout indicators by subgroup between now and the election). According to this second likely voter model, Obama has a 51% to 45% lead over McCain.
In order to not double count the Gallup Daily Tracking poll survey results in the RCP National Poll Average, and given Gallup has made a deliberate decision to release two "Likely Voters" results and has not indicated a preference as to which "Likely Voter" model they feel is most representative for the general election, RealClearPolitics will average Gallup's two "Likely Voters" results for the Gallup Daily Tracking numbers used in the RCP National Poll Average.