Assessing Reporting Delays in ACLED Conflict Event Data

Abstract

Timely and accurate conflict event data are essential for real-time monitoring, forecasting, and policy response. Yet near-real-time conflict datasets such as the Armed Conflict Location \& Event Data Project (ACLED) are subject to reporting delays, that is, delays between event occurrence and first inclusion in the database. Such delays can introduce bias in short-term analyses and forecasts. This study provides a statistical analysis of reporting delays for African events recorded in ACLED's weekly releases from June 30, 2024, to June 1, 2025. Treating delay as a discrete time duration, we estimate grouped proportional hazards models with additive-linear and smooth terms incorporating event-level, spatial, and country-level covariates. Our results show that more than half of events are reported within two weeks, but delays vary systematically by event type, fatalities, geographic location, and political regime. Higher-fatality events are reported more quickly, while events in more restrictive political and informational environments tend to be reported more slowly. We also find substantial between-country heterogeneity, and country-specific analyses indicate that event-level effects differ across contexts. These findings show that reporting delays are structured rather than random and that real-time conflict analysis must account for them. More broadly, they provide an empirical foundation for developing nowcasting approaches to correct short-term underreporting in conflict event data.

Figures (14)

• Figure 1: Sketch of reporting delay. The black (bottom) line shows the reported events at time point $t$. The blue (middle) line gives the numbers at $t+1$ and the green (top) line at $t+2$.
• Figure 2: Reported conflict events over time based on dataset download dates. The figure illustrates the number of events occurring between January 1 and June 24, 2024, as recorded in datasets downloaded on June 30, 2024, the following 4 weeks, and on December 24, 2024
• Figure 3: Kaplan--Meier curves of reporting delays: (a) first 100 weeks; (b) first 20 weeks by event type.
• Figure 4: Conflict events plotted over a map of Africa, with each point colored according to its reporting delay in weeks.
• Figure 5: Distribution of reporting delays in Cameroon and Sudan. Sudan shows a higher share of events reported early, whereas Cameroon has many more events with long reporting delays. Within-country variation is also visible: in Cameroon, delays are particularly pronounced in the South-West, while in South Sudan several highly delayed events appear near the southern border. These patterns highlight the presence of within-country heterogeneity in reporting delays.