My research currently is about political knowledge, but my last book was about what I call civic literacy. Australia, where you have compulsory voting, showed that there was some relationship between that and more informed voters. In other words, since you're required to vote, you go out and get more information.
So far, as far as I know, the research hasn't found that. Therefore, I'm not particularly in favour of simply getting more people to vote without at the same time getting people more informed about politics. If our turnout went way down and we ended up with a possibility of less than 50% turning out, I would look for more radical solutions such as compulsory voting. Fortunately, I think we have other alternatives at this point.