A pilot study is appropriate for determining feasibility of a larger study. Corner’s (2002) comments regarding saving time and money suggested feasibility to me. During the design process we must determine feasibility related to availability of a sample (who meets the requirements for our research question to be examined), the skills of the investigator, the actual costs associated with methods and sample, and the time required to complete the study (extremely important for doctoral students).
As you progress through the steps of the research process from review of the literature to presentation of results, feasibility is considered. As an example, some of my research studies required measuring melatonin in saliva and serum. After reviewing the literature, I discovered the feasibility of using these media to accurately measure changes in melatonin in humans, and responses to stimuli in animals. However, I also discovered the cost of such measures was expensive and required special training in the laboratory procedures. These considerations of feasibility added to methods selected and the timeline for my research.
As you develope your studies, keep in mind Corner's economics ideas. Each element of the research process feeds back to preceding ones in determining the most economical but valid and reliable methods for obtaining an answer.
Corner, P. D. (2002). An integrative model for teaching quantitative research design. Journal of Management Education, 26, 671-692.