Statistical controversies in clinical research: should schedules of tumor size assessments be changed?

Background: Time to progression (TTP) is often used as a primary end point in phase II clinical trials. Since the actual date of nadir and progression is never known, most calculated TTP are overestimated. This study evaluates the imprecision on the estimate of TTP under two hypothetical tumor kinetic settings and various assessment schedules.

A prediction model to estimate completeness of electronic physician claims databases.

Objectives: Electronic physician claims databases are widely used for chronic disease research and surveillance, but quality of the data may vary with a number of physician characteristics, including payment method. The objectives were to develop a prediction model for the number of prevalent diabetes cases in fee-for-service (FFS) electronic physician claims databases and apply it to estimate cases among non-FFS (NFFS) physicians, for whom claims data are often incomplete.

Design: A retrospective observational cohort design was adopted.