New and Improved(?) Tracking Poll Average: McCain's Slow Fade

by tremayne [courtesy of Open Left - Front Page]

The Reuters/C-Span/Zogby tracking poll debuted a few days ago and I've decided to add it to my tracking poll average. It fits the criteria: it's daily and based on a 3-day rolling average just like the four we've been using (Rasmussen, Gallup, Hotline and Research 2000/DailyKos). And remember, this is a Zogby phone poll, not their online polls which are notoriously erratic. Zogby's phone polls actually score higher for accuracy than Gallup according to Nate Silver's rankings.

I'm still not adding the GW/Battleground tracking poll because it's not daily, it's based on four days rather than three and has had reporting problems discussed in this Quick Hit. I've also decided not to weight the polls by sample size like they do at TPM. There's a certain logic to that approach but sample size is just one variable affecting a poll's accuracy. You can have a large sample and a bad result if, for example, your sampling procedure is bad or your weighting assumptions are wrong. And some pollsters tend to have a "left" or "right" bias. If you weight by sample size you might inadvertently exagerrate that. So we'll keep it simple and just average the five daily 3-day rolling average tracking polls.

Here's the trend for the last four days in the new tracking poll average:

John McCain's negative attacks may be causing a plateau in Barrack Obama's support but they are coming at the cost of his own support which appears to be doing a slow fade down towards 40 percent. We're only four days in to this new poll average so we'll have to see if that trend continues.