The document discusses different types of cross-sectional and cohort research designs used in marketing research. A cross-sectional design involves collecting information from a sample of a population once, while a multiple cross-sectional design collects information from different samples at different time points. Cohort analysis surveys the same group of respondents over time as they experience an event. An example case study tracks soft drink consumption in the US over 30 years in 10-year intervals by cohort.