Is international election observation credible? Evidence from Organization for Security and Co-operation in Europe missions

While international election observations missions often aim to present generalizable claims about the quality and integrity of an election, their findings are rarely based on a representative sample of observations, undermining the credibility of the missions. Bias in the selection of polling stations, among other things, can inflate or deflate the percentage of polling stations where observers find significant flaws. This article uses original data from Organization for Security and Co-operation in Europe (OSCE) election observation missions to illustrate the nature of the problem of selection bias in international election observation, and show how the percentage of ‘bad’ polling stations (in the absence of selection bias) can be estimated through a weighting procedure. The article finds that, while there is a strong degree of selection bias, this does not significantly impact the overall percentage of ‘bad’ polling stations that is reported by OSCE observation missions.