Regression with Count Data: Poisson and Negative Binomial

Poisson, quasi-Poisson, and negative binomial regression - when to do them and how you should choose the method. What are overdispersion and underdispersion, and why are they problems? How to deal with too many zero counts (zero-inflation) or when zero counts are impossible (zero-truncation). 0:00 Background 2:26 Poisson Regression: What and Why 7:05 Overdispersion: Quasi-Poisson or Negative Binomial 13:25 Zero-Inflation and Zero-Truncation 18:37 Summary Table