Determining sample size for avian mortality(and vice-versa)

- using data augmentation for epidemiology

Ken Rice1,2, Thomas Lumley1,3 , Betz Halloran1,4

1. University of Washington, Department of Biostatistics

2. Seattle Symphony Chorale

3. Seattle Choral Company

4. Statistical and Quantitative Methods for Infectious Diseases and Evaluating Interventions

West Nile Virus• King County wants you to be aware!

It’s working!

• Cases of West Nile in King County

0

0.13

0.26

0.39

2002 2003 2004 2005 2006 2007

BirdsHumansHorses

Avoiding misclassification

Before analyzing it;

• Is it a bird?• Is it a plain (bird)?• Is it dead?

“If you find a dead crow, blue jay, raven or pigeon”

Sample size – a reminder

• Power is low for rare events

• Low power =

lots of awkward questions to answer!

• How to increase sample size of dead birds?

Sample size – a reminder

• A hint!

• We don’t cover this in Autumn quarter, or Winter…

strychninecyanide