Abstract
The results of research on the effects of political campaign expenditures on congressional elections are somewhat mixed although most suggest that incumbent campaign spending has a minimal to no statistically significant effect on election outcomes, whereas challenger spending has a rather significant effect. This study differs from the prior research by including as an explanatory variable the percentage of registered voters who have the same party affiliation as the candidate. Results suggest that spending by both the incumbent and the challenger have significant effects on the percentage of votes obtained, while the percentage of own party affiliation has a positive, but minimal, effect. Finally, it was found that incumbents possess a 24-point advantage over their challengers; this result may partially explain why incumbents are re-elected over 90% of the time.