Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Geys. 2006. Explaining voter turnout: A review of aggregate-level research. Electoral Studies 25 (4): 637-663.
Geys examines three groups of variables in his meta-analysis. Within each group, he identifies possible indicators as strongly significant, significant, or inconclusive/insignificant, based on how frequently previous studies have identified each factor as significant.
Most studies in the analysis examine the U.S. case (see the appendix). Does this skew the results? (Geys does not include a dummy for each country, or even for the U.S., which might have addressed this concern.) Still, the strongest conclusion this paper makes is that future studies ought to include these variables as controls.
Variable selection involves normative decisions: ex: should scholars include ex-felons in states where the right to vote has been revoked for life, even though they are no longer serving time? While this is an empirical paper, the normative elements were not addressed, although claims were made: "Clearly one should be registered to be eligible to vote and to be able to register, one must fulfil all other elements of eligibility (e.g. age, civic rights)....Obviously, excluding those legally forbidden to vote should be preferred..." pg. 3. The absence of variables may be problematic (Geys disregarded age, education, and income). If the ecological fallacy can be methodologically overcome (King, 1997), why were these variables still left out? (see footnote 6).
This problem is severe. McDonald and Popkin (2001), which Geys does not cite, demonstrated that replacing the Census's measure of "voting age population" with a refined "voting eligible population" completely changes the trends in turnout. (The improved measure 'excludes' felons and the mentally incapable and 'includes' eligible but uncounted voters, like soldiers stationed overseas). As it turns out (according to McDonald and Popkin), turnout has not steadily declined over the past decades, as many had feared; rather, it spiked in the 1950s, then stabilized by around 1971.
"Population stability" measure actually captures SES (socio economic status). Homeownership and race, as well as homeownership and income are highly correlated. Geys provides a rational choice (seeking of benefits and avoidance of costs) argument for why homeowners show up at the polls more than non-homeowners. It seems a test to control for SES and triangulation of survey data would be necessary to support that this claim, and not other factors (e.g. feeling politically marginalized/ ineffectual) are at work. Further, one could argue that housing policy disproportionately impacts non-homeowners (impacting ability to purchase in the future due to government impacts on housing supply and affordability, property taxes for the provision of public schools and services).
Does previous turnout (strongly significant) reveal habitual voting or does it encapsulate numerous other factors (SES, sense of duty to vote)? Does saying "people turn out because they turned out in last election" not just beg the question of "why do people turn out"? Geys assumes this is "habitual voting", but there is insufficient proof of that. Compulsory voting seems to do the same loop: "Why do people turn out? Answer: because they have to". This simply does not help us answer the question of "why do people turn out when they don't have to". Both of these independent variables do not seem to add value in addressing the fundamental question "why do some people vote and others abstain?" While registration requirements suppressing turnout may have valuable policy implications (particularly if certain groups are inordinately affected), the inclusion of this variable does not directly get to the fundamental question either: "why would someone turn out to vote". Some could desire to turn out (show up at the polls but be turned away).
Inclusion of this variable is obviously important (or better yet use of first-differencing) for empirical reasons, but it is not clear that it has the theoretical consequences that we might like to believe.
Like many studies, this one finds that turnout goes up when elections are close; and like many studies, this one concludes that this finding validates the rational model of turnout. But recall what other authors have said: Being a foot taller may make you more likely to hit your head on the moon, but you still aren't going to do it. The probability of being decisive is still nill when the election is close. []
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