Comparing numbers is another form of collecting data in order to support the outcome of a debatable topic. For example with the 2020 presidential election, each state compared numbers in not only the votes given to each candidate but also how the electoral college could factor in the results of the election.
News stations even compared numbers in regards to the 2016 and 2020 election.
While comparing numbers is useful in data collection it does not supply you with all factors behind situations. In research you should compare numbers as well as other methods of research.
https://www.businessinsider.com/2016-2020-electoral-maps-exit-polls-compared-2020-11