Jonathan Freeman, Donald A. Goldmann and John E. McGowan, Jr. Most information in hospital epidemiology comes from observational studies of hospitalized patients, not from planned experiments. Data ...

Confounding is recognized as a mixing of effects that can lead to spurious conclusions about the association between disease and a putative risk factor. Confounding occurs if an extraneous factor ...

Selection bias: occurs when the study population is not representative of the target population, leading to inaccurate conclusions. Confounding bias: occurs when an extraneous variable is related to ...