An observational study is an empirical investigation of the effects of treatments, policies or exposures. It differs from an experiment in that the investigator cannot control the assignment of treatments to subjects. Scientists across a wide range of disciplines undertake such studies.

Includes supplementary material: sn.pub/extras

Inhalt
1 Observational Studies.- 2 Randomized Experiments.- 3 Overt Bias in Observational Studies.- 4 Sensitivity to Hidden Bias.- 5 Models for Treatment Effects.- 6 Known Effects.- 7 Multiple Reference Groups in Case-Referent Studies.- 8 Multiple Control Groups.- 9 Coherence and Focused Hypotheses.- 10 Constructing Matched Sets and Strata.- 11 Planning an Observational Study.- 12 Some Strategic Issues.