The study relies on self-reported data from telephone interviews, which can be prone to recall bias and social desirability bias. Participants may not accurately remember the number of accidents they had or may underreport risky driving behaviors.
The study only includes drivers from one county in Alabama, limiting the generalizability of the findings to other populations. Different regions may have different driving habits, road conditions, and access to healthcare, which could influence accident rates.
While the study identifies several significant factors associated with accidents, it doesn't establish causality. The observed associations could be due to unmeasured confounding variables.
The GPR model, while better than the PR model, might not be the most appropriate model for this kind of count data. It assumes certain distribution characteristics that might not be true in reality. Other count data models might have been a better fit and yielded different conclusions.
The study's exclusion of a large portion of the original sample due to missing data creates a risk of selection bias. The excluded cases may be different from the remaining ones which weakens the generalizability of the findings.