SEIDR model parameter estimates. SEIDR model parameter estimates for three models for each of the 7 seasons. The parameters are transmission parameter (top right), epidemic offset (bottom left), and detection fraction (bottom right). The estimates from the model with 1) all parameters varying by epidemic year are open triangles, 2) transmission parameter constant across epidemic year are plus signs, and 3) detection fraction constant across epidemic year are x's. The data were collected by Primary Children's Medical Center, Salt Lake City, UT from July 2001 through June 2008.