An examination of Gallup's polling methods is now shedding light on the unwarranted swing in public opinion. The earlier poll which showed a Republican advantage polled registered voters, while Democrats lead among a wider sample of all adults.
However, Gallup doesn't point out this subtle difference in polling methods, leading us all to believe that Democrats had actually made quite a resurgence in the polls.
It seems a bit dishonest for Gallup not to differentiate between the two polls to and present the results as ongoing trends when the different data sets inevitably lead to different statistical outcomes.
RedState suggests that Gallup is lying, purposefully misleading with their polling methods. I'm not sure if I'd go that far--we'll see what their next poll looks like. But I'll readily admit this latest episode seems like trickery and agree with RedState's final assessment:
You cannot pretend that a poll of all adults and a poll filtered by registered voters are part of the same series, even if the same questions are asked. That’s Polling 101, and whoever’s responsible for the Gallup release should have known this, and certainly whoever’s responsible for oversight of the Gallup releases would know this.