Discuss the difference between longitudinal and cross-sectional research designs.
Answer
Cross-sectional design is the most familiar and most common way of conducting marketing research. It includes collection of information from any given sample of population elements only once. Objective of cross-sectional design many times is to establish categories such that classification in one category implies classification in one or more other categories.
A longitudinal design is much more reliable than a cross-sectional design for monitoring changes over time as it relies less on consumers' mental capabilities and more frequently monitors events as close to their time of occurrence as feasible. Primary objective of longitudinal design is to monitor change over a period of time. It involves a fixed sample of population elements which is measured repeatedly. Sample remains the same over a period of time hence providing a series of pictures when, which viewed together, portray a detailed explanation of situation and changes which are taking place over a period of time.