Introduction: The COVID pandemic is a challenge for public health surveillance and an opportunity to assess its strengths and weaknesses to improve the response .
Objective: To evaluate the performance of the Colombian public health surveillance system during the first 50 days of the COVID-19 pandemic in the country . Materials and methods: We analyzed the data published between March 6 and April 24 , 2020, by the Instituto Nacional de Salud and the World Health Organization (WHO). We evaluated: i) the quality of the data according to the fulfillment of Benford's law, and ii) the timeliness of the information measured as the difference in dates between the data generated by the Instituto Nacional de Salud and WHO's situational reports . We assessed the fulfillment of Benford's law using the p values of the log-likelihood ratio, the chi square or Moreno's exact tests .
Results: Until April 24 there were 4,881 cases of COVID-19 in Colombia . During most of the first 50 days of the pandemic, Benford's law was fulfilled except the first days of the epidemic . The difference between Instituto Nacional de Salud and WHO reports largely depends on the different reporting times . Conclusion: In general, the Colombian public health surveillance system fulfilled Benford's law suggesting that there was quality in the data . Future studies comparing the performance of the departments and districts will improve the diagnosis of the Colombian surveillance system.