Despite the greater diversity of the Texas legislature in recent years, one of the factors that has maintained continuity with traditional patterns in the make-up of the membership is the advantage of incumbency. Historically, there has been very slow turnover of the membership: a pattern that continues today. The 2007 - 2008 Senate, for instance, had only five members, or about 6.2 percent, who were new. In that same legislature, the House, with its shorter terms of office, had twenty-three new members, or 15 percent. The 2009 Senate will have two new members and the House will have 20. (Among these 20 new members, only one was the result of a defeated incumbent.)

Incumbency is a huge advantage when running for legislative office because it allows more opportunities for name recognition: a critical advantage because of the large number of offices for which Texans vote. As voters move down the ballot (to "down-ballot" contests like those for state legislator), they have to rely on less and less knowledge of the candidates. Often voters will vote for a candidate in these races simply because they recognize - or think they recognize - the candidate's name.

Incumbency also helps candidates raise campaign money from powerful special interests. If you've supported a special interest's position on legislation, they will reward you. But, only incumbents have this opportunity. As a general rule, special interests will bet more money on an incumbent than a challenger because of the expectation that the incumbent will win. Even where special interests see challengers as equally supportive, incumbents are likely to get more money, because they are more likely to win. For special interests, it's almost like betting on the horses: often they don't particularly care who wins, but they want to be on the winning side.

The state's much more competitive political environment, combined with redistricting, generated a relatively high turnover rate in the 78th Legislature. These factors contributed to the ability of the Republican Party to finally gain its long sought after majority in both the House of Representatives and the Senate.

Despite its importance in determining the membership of the Texas legislature, incumbency is less of a factor there than it is in the United States Congress, as comparison of historical incumbency success rates in the two bodies illustrates.