I am conducting a case study research on the fight against gentrification through the use of public policies in Brazilian and foreign cities. Thanks for any suggestions.
Mr. Paulino my suggestion is first you chose particular public policy/policies related to the issue for your study. Then you chose city/cities as your universe and select sample size (population) using by appropriate methodology such as random sampling/purposive sampling as your appropriateness. If you wanted to comparative study between city/cities from Brazil and other country, might be follow same methodology. Wishing your success.