Exploration of the Potential Correlation Between Population Density and Rat Infestation

Yussef Ibarra, Sarafina Lin, Diana Ulivanova, Nafisa Zaforullah

Our study was conducted to determine if a correlation exists between rat population and population density across New York City. The goal was to help the city improve sanitation efforts by finding a cause to the problem. Rats are a major public health issue because they can carry and spread many diseases. This problem is becoming even more apparent as outdoor dining is expanding in response to the pandemic. We expected a greater human population density to be correlated with a higher rat population. To test this hypothesis, we divided the city into community districts. We also used the frequency of rat observations as a proxy for the true rat population by assuming that a greater rat population would mean people see them more. We then compiled the total sightings and complaints of rats from iNaturalist and NYC Open Data for the first 6 months of 2020 in their respective districts, for which we conducted a linear regression test against population density. With a correlation coefficient of 0.4371, there was a weak correlation between population densities across community districts in NYC and their corresponding rat sightings. Notably, Manhattan and Brooklyn were among the most rat sightings on average. Since our hypothesis was not supported, in the future we would study other factors that may influence rat populations such as garbage volume and the number of residential units.