A Closer Look at Reporting Bias in Conflict Event Data
Recent data collections about political violence are frequently based on media reports, which can lead to reporting bias. This is an issue in particular for the emergent literature on communication technology and conflict, since this technology may not only affect violence, but also the reporting about it. Using the effect of cellphones on violence as an example, this article presents a quantitative assessment of reporting bias in a micro level analysis. Comparing media based event reports and those from military sources, the results show that the purported violence increasing effect of cellphone coverage is partly due to higher reporting rates of violence in cellphone covered areas. A simple diagnostic procedure for this problem is implemented. Applied to the analysis of cellphones and violence in Africa, it produces a pattern that is consistent with reporting bias driving much of the effect found in the Pierskalla and Hollenbach (2013) study about this topic.