A student's research shows that there were more car accidents in 2015 than there were in 1915. He concludes that people were better drivers in 1915 than in 2015.
Why is it not valid to use these two numbers to assess driving abilities in these two years?

Question

Quizplus · Accepted Answer

The increase in the number of cars on the road is a significant factor that could have contributed to the increase in accidents. This means that concluding that people were better drivers in 1915 is not a valid deduction based solely on the number of car accidents. A comparison between two years with different numbers of cars on the road would not be a fair comparison.

A Student's Research Shows That There Were More Car Accidents