Incumbency Reconsidered: Prospects, Strategic Entry, and Incumbent Quality in U.S. House Elections

Efforts to estimate the magnitude of the incumbency effect in U.S. House elections and assess its political meaning have been complicated by two omitted-variables problems. First, in the absence of an adequate measure of incumbent prospects, estimates of the magnitude of the incumbency effect fail to control for selection effects associated with the decision incumbents make about whether to run for reelection. Strategic incumbents enter races they think they can win and withdraw when they expect to lose. The consequence is an upward bias in estimates of incumbents’ electoral advantages. Second, the normative implications of high reelection rates cannot be assessed without measuring incumbent quality, since a possible explanation for their electoral success is that incumbents are of high quality and doing a good job. We propose a strategy for measuring incumbent prospects and quality, demonstrate the strategic nature of incumbent and challenger entry, re-estimate the incumbency effect, and show that incumbent quality has an impact on electoral outcomes. Our conclusion is that incumbents’ advantages in House elections have been over estimated while the positive basis of incumbent safety is typically under appreciated.

MODELING POTENTIAL TIGER HABITAT IN HUPINGSHAN-HOUHE ANDMANGSHAN-NANLING NATIONAL NATURE RESERVES, CHINA

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Modeling Potential Tiger Habitat in Hupingshan-Houhe and Mangshan-Nanling National Nature Reserves, China

After declining steadily for several decades, the South China tiger (Panthera tigris amoyensis) is now thought to be extinct in the wild. However, there is some hope of reintroduction, with Hupingshan-Houhe and Mangshan-Nanling National Nature Reserves in southern China seeming to hold the most promise. Our study used slope, elevation, vegetation, and landcover variables to construct a rough habitat suitability index for tigers in these two parks. According to our model, there are areas of suitable habitat within both parks. However, there are some important variables that we were unable to include in our model, such as human population density and prey availability. Considerable in-depth research will be necessary to evaluate the suitability of these locations before reintroduction is considered.