"Tightness" of political elections and public attention Are there any empirical studies on political elections that focus on the "tightness" of the race and how much attention the election receives from the public (or perhaps voter turnout).

By "tightness" I mean ex ante probabilities of winning the election are not too different among the candidates. 

I suspect that tight races should be able to garner more public attention, but I would like some evidence to back this up.
Yes, you should look at the regression discontinuity literature in political economy that uses close elections as the identification strategy. For example, see http://sekhon.berkeley.edu/papers/CaugheySekhonRD.pdf  and http://www.polmeth.wustl.edu/media/Paper/EggersetalRDD.pdf