Do Elections Trigger Mass Atrocities?

Kenya plans to hold general elections in early March this year, and many observers fear those contests will spur a reprisal of the mass violence that swept parts of that country after balloting in December 2007.  The Sentinel Project for Genocide Prevention says Kenya is at “high risk” of genocide in 2013, and a recent contingency-planning memo from Joel Barkan the Council on Foreign Relations asserts that “there will almost certainly be further incidents of violence in the run-up to the 2013 elections.” As a recent Africa Initiative backgrounder points out, this violence has roots that stretch much deeper than the 2007 elections, but the fear that mass violence will flare again around this year’s balloting seems well founded.

All of which got me wondering: is this a generic problem? We know that election-related violence is a real and multifaceted thing. We also have works by Jack Snyder and Amy Chua, among others, arguing that democratization actually makes some countries more susceptible to ethnic and nationalist conflict rather than less, as democracy promoters often claim. What I’m wondering, though—as someone who has long studied democratization and is currently working on tools to forecast genocide and other forms of mass killing—is whether or not elections substantially increase the risk of mass atrocities in particular, where “mass atrocities” means the deliberate killing of large numbers of unarmed civilians for apparently political ends.

Best I can tell, the short answer is no. After applying a few different statistical-modeling strategies to a few measures of atrocities, I see little evidence that elections commonly trigger the onset or intensification of this type of political violence. The absence of evidence isn’t the same thing as evidence of absence, but these results convince me that national elections aren’t a major risk factor for mass killing.

If you’re interested in the technical details, here’s what I did and what I found:

My first cut at the problem looked for a connection between national elections and the onset of state-sponsored mass killings, defined as “a period of sustained violence” in which ” the actions of state agents result in the intentional death of at least 1,000 noncombatants from a discrete group.” That latter definition comes from work Ben Valentino and I did for my old research program, the Political Instability Task Force, and it restricts the analysis to episodes of large-scale killing by states or other groups acting at their behest. Defined as such, mass killings are akin to genocide in their scale, and there have only been about 110 of them since 1945.

So, do national elections help trigger this type of mass killing? To try to answer this question, I thought of elections as a kind of experimental “treatment” that some country-years get and others don’t. I used the National Elections Across Democracy and Autocracy (NELDA) data set to identify country-years since 1945 with national elections for chief executive or legislature or both, regardless of how competitive those elections were. I then used the MatchIt package in R to set up a comparison of country-years with and without elections within 107 groups that matched exactly on several other variables identified by prior research as risk factors for mass-killing onset: autocracy vs. democracy, exclusionary elite ideology (yes/no), salient elite ethnicity (yes/no), ongoing armed conflict (yes/no), any mass killing since 1945 (yes/no), and Cold War vs. post-Cold War period. Finally, I used conditional logistic regression to estimate the difference in risk between election and non-election years within those groups.

The results? In my data, mass-killing episodes were 80% as likely to begin in election years as non-election years, other things being equal. The 95% confidence interval for this association was wide (45% to 145%), but the result suggests that, if anything, countries are actually somewhat less prone to suffer onsets of mass killing in election years as non-election years.

I wondered if the risk might differ by regime type, so I reran the analysis on the subset of cases that were plausibly democratic. The estimate was effectively unchanged (80%, CI of 35% to 185%). Then I thought it might be a post-Cold War thing and reran the analysis using only country-years from 1991 forward. The estimate moved, but in the opposite of the anticipated direction. Now it was down to 60%, with a CI of 17% to 215%.

These estimates got me worried that something had gone wacky in my data, so I reran the matching and conditional logistic regression using coup attempts (successful or failed) instead of elections as the “treatment” of interest. Several theorists have identified threats to incumbents’ power as a cause of mass atrocities, and coups are a visible and discrete manifestation of such threats. My analysis strongly confirmed this view, indicating that mass-killing episodes were nearly five times as likely to start in years with coup attempts as years without, other things being equal. More important for present purposes, this result increased my confidence in the reliability of my earlier finding on elections, as did the similar estimates I got from models with country fixed effects, country-specific intercepts (a.k.a. random effects), and interaction terms that allowed the effects of elections to vary across regime types and historical eras.

Then I wondered if this negative finding wasn’t an artifact of the measure I was using for mass atrocities. The 1,000-death threshold for “mass killing” is quite high, and the restriction to killings by states or their agents ignores situations of grave concern in which rebel groups or other non-state actors are the ones doing the murdering. Maybe the danger of election years would be clearer if I looked at atrocities on a smaller scale and ones perpetrated by non-state actors.

To do this, I took the UCDP One-Sided Violence Dataset v1.4 and wrote an R script that aggregated its values for specific conflicts into annual death counts by country and perpetrator (government or non-government). Then I used R’s ‘pscl’ package to estimate zero-inflated negative binomial regression (ZINB) models that treat the death counts as the observable results of a two-stage process: one that determines whether or not a country has any one-sided killing in a particular year, and then another that determines how many deaths occur, conditional on there being any. In addition to my indicator for election years, these models included all the risk factors used in the earlier matching exercise, plus population size and the logged counts of deaths from one-sided violence by government and non-government actors (separately) in the previous year. All of these variables were included in the logistic regression “hurdle” model; only elections, population size, and the lagged death counts were included in the conditional count models.

To my surprise once again, the results suggested that, if anything, atrocities the risk of mass atrocities is actually lower in years with national elections. In the model of government-perpetrated violence, the coefficient for the election indicator in the hurdle model was barely distinguishable from zero (0.04), and the association in the count portion was modestly negative (-0.20, s.e. of 0.20). In the model of violence perpetrated by other groups, the effect in the hurdle portion was modestly negative (-0.25, s.e. of 0.20), and the effect in the count portion was decidedly negative (-0.82, s.e. of 0.19). When I reran the models with separate indicators for executive and legislative elections, the results bounced around a little bit, but the basic patterns remained unchanged. None of the models showed a substantial, positive association between either type of election and the occurrence or scale of one-sided violence against civilians.

In light of the weakness of the observed effects, the noisiness of the measures employed, and my prior beliefs about the effects of elections on risks of mass killing—shaped in part by the Kenyan case I discussed at the start of this post—I’m not quite ready to assert that election years actually reduce the risk of mass atrocities. What I am more comfortable doing, however, is ignoring elections in statistical models meant to forecast mass atrocities across large numbers of countries.

If you’re interested in replicating or tweaking this analysis, please email me at, and I’ll be happy to send you the data and R scripts (one to get country-year summaries of the UCDP data, another to run the matching and modeling) I used to do it. [UPDATE: I’ve put the scripts and data in a publicly accessible folder on Google Drive. If you try that link and it doesn’t work, please let me know.] Ideally, I would cut out the middleman by putting them in a Github repository, but I haven’t quite figured out how to do that yet. If you’re in the DC area and interested in getting paid to walk me me through that process, please let me know.

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