Estimating the differences in police and hospital records of people injured in traffic crashes in Dire Dawa City administration, Ethiopia

The management of road safety relies on data from road traffic crashes to identify priorities, monitor trends and evaluate interventions. Both police and hospital records are important sources of information on crashes that result in injury; however, both are known to be incomplete, with the quality and completeness of data being lower in low- and middle-income countries. The aim of this study is to estimate the magnitude of the underreporting of crashes in Dire Dawa City, Ethiopia, as a case study that may be applicable elsewhere. In addition, it gives an opportunity to understand the discrepancies between police and hospital records in Dire Dawa City and how the data systems work in the city. This research compared data on traffic collisions resulting in injury from July 2014 to February 2019 across police and hospital databases and used the capture-recapture technique to estimate the actual numbers of crashes and the degree of under-recording in both sources. It was found that there was substantial under-recording in both sources, with the degree of under-recording varying by urban/rural area, gender, age, road user category and injury severity, as well as by source within these variables. The police figures were lower than the hospital figures, and in all cases but three (rural areas, passengers and serious injury crashes), both sources had more unmatched than matched cases. In addition, the analysis discovered undocumented deaths and injuries in both databases. To summarize, police capture more death instances, but hospitals capture more serious injury cases. The capture-recapture strategy predicted a greater number of instances than currently recorded by police and hospitals. This demonstrates a major under-reporting of crash data from both sources. This level of under-recording can lead to less effective road safety management and evaluation. Replication of this research in other parts of Ethiopia could provide information on local practices that are more or less successful in reducing the level of under-recording, and such results may have implications for other countries with similar problems.