Article,
Detecting Bias with Confidence in Observational Studies
Biometrika, 79 (2): 367--374 (1992)
Abstract
In an observational study, detecting hidden bias involves
checking that treatment effects appear where they should,
and not elsewhere. For instance, treated and control groups
are often compared with respect to outcomes the treatment
should not affect. This paper uses such a test for bias to
obtain a confidence set for an unobserved covariate. The
impact of this unobserved covariate is indicated by a
sensitivity analysis with the covariate confined to the
confidence set. In this way, a test for bias may indicate
either the presence and magnitude of a hidden bias or else
a reduction in the sensitivity to bias.
