From Academic Kids
Psephology is the predictive or statistical study of elections. (From the ancient Greek psephos, 'pebble', which the Greeks used as ballots.) Psephology is possible for a variety of reasons: the compilation of precinct voting returns for all elections going back many years, the publication of numerous public opinion polls asking similar questions on many different dates, and the public availability of campaign finance information. As a result of all these, and other factors, there are fewer and fewer election result surprises over time.