Poisson Regression with Rates

1
Poisson Regression with Rates

• Traffic Deaths in Finland on Friday the 13th and
  Other Fridays 1971-1997
• Simo Näyhä (2002). Traffic Deaths and Superstion
  on Friday the 13th, American Journal of
  Psychiatry, Vol. 159, 12, pp. 2110-21111

2
Data

• Traffic Deaths and Exposure by Gender on Friday
  the 13th and Other Fridays in Finland for years
  1971-1997
• Traffic Deaths are Given as Counts by Friday type
  and gender
• Exposure is person days (100,000s)

3
Poisson Model for Rates
4
Likelihood and ML Estimates - I
5
Likelihood and ML Estimates - II
6
Friday the 13th Results Regression Coefficients
7
Predicted Values, Residuals, Risk Ratios
8
Friday the 13th Results
TDRTraffic Death Rate (per 100,000 exposed)
Males tend to have higher accident death rates
than females. The Friday the 13th effect is not
significant for males (Risk Ratio interval
contains 1). The Friday the 13th Effect is
significant for females (Risk Ratio interval is
entirely above one)
9
(No Transcript)