observatorbias
Observatorbias, commonly referred to as observer bias, is a systematic error that occurs when an observer's expectations, beliefs, or prior knowledge influence the collection, recording, or interpretation of data. It is especially likely in studies requiring subjective judgments, coded observations, or transcription of qualitative material, though it can affect quantitative measurements as well.
Causes include selective attention to events that confirm expectations, biased coding of behaviors, the halo effect,
Observer bias arises in psychology, medicine, education, ethnography, and any research relying on human judgment. It
Examples: the experimenter expectancy effect, where researchers’ beliefs influence participants’ responses; biased scoring on rating scales;
Mitigation: blinds or masking of observers to experimental conditions, or even to study hypotheses; use of objective,
Impact: when present, observatorbias can distort effect sizes, inflate false positives, or obscure true relationships, threatening
See also: observer effect, confirmation bias, measurement bias, inter-rater reliability.