Suppose that dunkin donuts solicited a group of customers to provide feedback on its products over time; for example, completing a survey every six months over a period of years. what marketing research technique would this represent?

The answer is panel data. It is also known as longitudinal data or cross-sectional time series data is data that is resulting from a (typically small) number of comments over time on a (typically large) number of cross-sectional units like individuals, households, firms, or governments. In the field of econometrics and statistics, panel data talks about to multidimensional data that generally includes measurements over some period of time. As such, panel data contains researcher's explanations of numerous occurrences that were collected over numerous time periods for the same group of units or entities.