Bias
- Bias – a flaw in impartiality that alters the manner in
which measurement, analysis, or assessment is recorded, conducted,
or interpreted.
- Randomization – controls the bias that would otherwise be
introduced by confounding variables
- other types of bias exist
- Blinding – controls bias that arises when experimenters
have information about study subjects that may compromise their
impartiality
- Strict adherence to the study protocol minimizes bias
- Selection bias is introduced by a nonrandom selection of a
sample from a given population
- Example: only athletes used in the study. They recover quickly.
- Observational or informational bias occurs when a
measurement/outcome is affected by the characteristics of the study
group itself
- Example: survey mailed to participants; some are homeless.