Sunday April 30, 2006--Thirty-eight percent (38%) of Americans now approve of the way George W. Bush is performing his job as President. Sixty-one percent (61%) disapprove.

One of the major methodological disputes among public opinion pollsters involves weighting data by Political Party. All agree that partisan affiliation is one of the best indicators of voting intentions and perceptions of the President. However, some firms and academic researchers believe that party affiliation changes on a regular basis. At Rasmussen Reports, we do not. We, along with many others, believe party affiliation is generally stable and that people switch their allegiance only rarely.

This view is supported by data and by common sense --how many people do you know that switch political parties on a regular basis?

The challenge for a polling firm is determining the proper partisan mix for a polling sample. What percentage of Americans are Republican, Democrat, or unaffiliated? What are the "right" numbers?

Beginning today (Sunday), Rasmussen Reports Job Approval updates are based upon data using a slight modification to our targeting and weighting process. From this point forward, we will set our partisan affiliation weighting targets based upon survey results obtained during the previous three months. These shift only modestly month-to-month, but the change could be significant over a long period of time.

Based upon the past three months, the current targets are 36.6% Democrat, 33.5% Republican, and 29.9% Unaffiliated. These targets will be updated monthly. Previously, our weighting targets assumed an equal number of Republicans and Democrats.

We have adopted this system because we believe it allows us to maintain the day-to-day stability needed to follow trends while adjusting periodically for any substantive shifts in partisan affiliation (see trends in party affiliation).

The practical impact of this revision is modest in the current environment. The new approach will result in the President's reported ratings being a point or two lower than they would have been under the old system. Today's reading would have been 39% using the old approach.

Data in the table to the right shows month-by-month Job Approval averages using the new weighting methodology. Each month's number is based upon interviews with approximately 15,000 American adults. The full month average for April will be released tomorrow (Monday). At that time, we will also update our month-by-month summary of shifting party affiliation among the general public.

By way of comparison, the President's decline in support among Republicans over the past two months has had a much bigger impact on his overall ratings than our procedural change. If the President had retained consistent support from his own party over the past few months, his Approval ratings would still be in the mid-forties.

Commentary:
The country shifts towards one party or the other a lot. After 911, all the polls gave republicans huge advantages. It's not the job of polling companies to decide the party mix. Instead, they should do random calls and at the end ask their party affiliation. Booting someone's response because he doesn't fit the right party will never work.