A pilot study, pilot project or pilot experiment is a small scale preliminary study conducted in order to evaluate feasibility, time, cost, adverse events, and improve upon the study design prior to performance of a full-scale research project. Pilot studies, therefore, may not be appropriate for case studies.
Pilot experiments are frequently carried out before large-scale quantitative research, in an attempt to avoid time and money being wasted on an inadequately designed project. A pilot study is usually carried out on members of the relevant population, but not on those who will form part of the final sample. This is because it may influence the later behaviour of research subjects if they have already been involved in the research.
A pilot experiment/study is often used to test the design of the full-scale experiment which then can be adjusted. It is a potentially valuable insight and should anything be missing in the pilot study it can be added to the full-scale (and more expensive) experiment to improve the chances of a clear outcome.
In sociology, pilot studies can be referred to as small-scale studies that will help identify design issues before the main research is done.
Although pilot experiments have a well-established tradition in public action, their usefulness as a strategy for change has been questioned, at least in the domain of environmental management. It is argued that extrapolation from a pilot study to large scale environmental strategy cannot be assumed to be possible, partly due to the exceptional resources and favourable conditions that often accompany a pilot study.