Our first step was to establish a process to determine the absence of news. We explored articles on violence to understand how they compare to the government's official registry of homicides. In theory, each murder that occurs ought to correspond with at least one local report about the event. If we saw a divergence, or if the government's reports were suddenly very different from local news coverage, we could deduce that journalists were being silenced.
Early on, sorting through news articles seemed impossible. We knew we needed to find a news archive with the largest number of publications in Mexico possible so we could track daily coverage across the country. Google News’ vast collection of local and national news stories across Mexico was a good fit
The effort required us to identify the difference between the number of homicides officially recorded and the news stories of those killings on Google News. This required machine learning algorithms that were able to identify the first reported story and then pinpoint where the event took place. With that information, we were able to connect reported events by media with the government's reports on homicides across more than 2400 municipalities in Mexico.
El Universal's algorithm detected several “silent zones” or “news deserts” (their terms), regions where there's a great disparity between the murders that appear in official statistics and those reported in news media. The resulting story, maps, and graphs show the total number of murders per year in comparison to rates and news coverage.
