The reality is that Republicans will likely comprise around 70-75% of the Republican primary electorate in every GOP primary state on average, with certain exceptions for states like New Hampshire. Nevertheless, the Washington Post and NBC News are putting out GOP primary polling that dramatically overestimates the percentage of independents that will vote in GOP primaries.
The Washington Post’s GOP primary poll is composed of all Republicans and Republican-leaning independents. NBC’s GOP primary poll is composed of not only all Republicans and Republican-leaning independents but all strict independents. Strict independents are independents that do not lean towards either the Republican or Democrat Party. Very rarely will these type of independents vote in either party’s primary. The types of independents that will vote in a GOP primary are independents that lean towards the Republican Party but it’s still a stretch to believe that GOP-leaning independents will comprise as large a percentage of the GOP primary electorate as the percentage claimed by the Washington Post and NBC News.
The Washington Post doesn’t tell you that Republican-leaning independents compose 42.5% of its GOP primary sample. NBC News doesn’t tell you that Republican-leaning independents and strict independents compose 58% of its GOP primary sample. Strict independents comprise 36% of its primary sample. The NBC News’ pollster actually believes that a sample that shows independents outnumbering Republicans by 16% is representative of the actual Republican primary electorate.
It’s a fair assumption to believe that Governor Palin is performing better among Republicans than she is among Republican-leaning independents. It’s also reasonable to believe that Palin is performing better among Republicans and Republican-leaning independents than she is among strict independents.
I suspect her five-point deficit to Romney in the NBC News poll and the two-point deficit to Huckabee in the Washington Post poll would be smaller or gone completely had either pollster included fewer independents in their samples. Independents are only expected to comprise 33-35% of the GOP primary electorate even in New Hampshire.
To conclude, the Washington Post got it half-right by only polling for Republicans and Republican-independents but it still erred by including all Republican-leaning independents. NBC News didn’t get anything right as it included all strict independents, the type of independents that rarely vote in primaries, in addition to including all Republican-leaning independents in its sample. It’s simply unreasonable to believe that on average independents will comprise over 40% (or almost 60% in the case of NBC News) of the GOP primary electorate, let alone in states with a lot of independents like New Hampshire.