WASHINGTON — Reeling from drubbings in three special elections in the past two months, House Republicans yesterday unveiled a series of tactical and personnel changes at their campaign arm designed to forestall more losses in November.

After losing seats in Republican strongholds in Mississippi, Louisiana, and Illinois, rank-and-file House members have grown more critical of the leadership of the National Republican Congressional Committee chairman, Tom Cole of Oklahoma, and the House Minority Leader, John Boehner of Ohio, who have repeatedly butted heads themselves.

The two men agreed on a prescription that includes a detailed “audit” — run by Republican Reps. Tom Davis of Virginia and Pat Tiberi of Ohio — of the mistakes made in the three special-election losses.

“Did the advertising work well, or didn’t it work well? How was the ground game?” Mr. Boehner asked. “There’s a lot that we can learn out of those three races that will help us as we set ourselves up for the fall.”

The most significant move announced yesterday was a change in the party’s approach to competitive Republican primaries. Leaders will now wade into those contests to help the best generalelection candidates emerge, a shift from Mr. Cole’s previous decision to stay out of primaries. In the Illinois and Louisiana special elections, party leaders believe that chances of success were hampered by subpar nominees.

Republican nominees also will be aided by the establishment of new fundraising committees that will collect cash during the primaries and turn it over to the eventual winner for the general election. And Mr. Boehner is installing a key ally, Ed Brookover of the consulting firm Greener & Hook, in the upper echelons of the NRCC.