Description (provided by applicant): The Risk Characterization Core of the University of Washington Center for Child Environmental Health Risks Research (1998-2003) has had the following specific aims: 1) Provide statistical collaboration and consultation on study design and data analysis, 2) Develop new methods for study evaluation, 3) Develop and characterize new risk assessment methods that specifically improve models used for assessing children's environmental risks, and 4) Collaborate in the writing of manuscripts.