This presentation discusses understanding local populations and issues with population data and projections. It notes challenges including a lack of single comprehensive data source, outdated estimates that don't reflect diversity, and inaccuracies from using short-term immigration trends to make long-term projections. Improving data requires regular updated systems covering demographics like ethnicity and birthplace. Caution is urged against getting "transfixed" on data limitations or pursuing "perfection" if existing information is adequate for decision-making.