World Health Organization’s estimates of death related to road traffic crashes and their discrepancy with other countries' national report

Due to a lack of effective registry system for road traffic deaths, some international organizations like the World Health Organization provide the estimated number of road traffic deaths. It was shown that there are differences in the number of road traffic deaths between the WHO estimates and national reports even in High-Income Countries. This study aimed to an investigation of reasons for differences between the national reports and world health organization estimates about road traffic deaths. Methods: This study focus to investigate the World Health Organization reports of Global Status Report for Road Safety in years of 2009, 2013, 2015 and 2018 and related articles about the estimates of deaths related to road traffic crashes and the observed differences between the WHO estimates and national reports. Results: The findings showed that the observed differences between the WHO estimates and national reports could be due to errors in the road traffic death registration system, errors in the regression model which was used for estimation, proposed variables for estimations, or all of them. Conclusions: The estimations of WHO about road traffic deaths can be useful for countries especially for those which don’t have the road traffic registry system or the registry system does not meet the quality criteria. These estimates may not be sufficiently robust if disregard for spatial differences, the epidemiological pattern of risk factors among the countries, and the type of regression model which was used for estimation