Small scale prototype of study carried out in advance of full research to find any problems e.g.
Experimental design- Do p have enough time to complete task.
Instructions for participants- If clear enough.
Measuring instruments- Inc behav cat in obs res and questions when questionaires used. Allow for cat and ques to be check and modified where necessary.
Carry out pilot study beforehand way to ensure time, effort and money not wasted on flawed methodology. Import that pilot study uses sample that representative of target pop that be used in main res.