Learning that occurs as a function of observing, retaining and, in the case of imitation learning, replicating novel behavior executed by other people.

Study involving no experimental manipulation.

In marketing and the social sciences, observational research (or field research) is a social research technique that involves the direct observation of phenomena in their natural setting.

(statistics) The difference between a measured value of a quantity and its true value.

Indistinguishable outcomes under different conditions.

the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors.