8.2 The arguments you have listed should focus on the following issues: • The study suggested by the research question requires historical data so that changes that have already happened can be explored. These data will, by definition, have already been collected. • The timescale of the research (if part of a course) will be relatively short. One solution for longitudinal studies in a short time frame is to use secondary data. • The research question suggests an international comparative study. Given your likely limited resources, secondary data will provide the only feasible data sources.