Final answer:
An impact assessment is the best tool to determine the potential differential impact of a policy on various populations, as it systematically evaluates potential effects and integrates data from surveys, focus groups, and data analysis.
Step-by-step explanation:
A good tool to help determine the potential differential impact of a policy on various populations would be an impact assessment. An impact assessment is a systematic process that evaluates the potential social, economic, and environmental effects that a policy may have on different groups within a community. Methods such as surveys and focus groups can contribute to an assessment by gathering qualitative and quantitative data from affected populations. Meanwhile, data analysis plays a critical role in interpreting the information collected to understand the broader implications of the policy. Surveys, for example, gather both quantitative and qualitative data and are beneficial when exploring the opinions, behaviors, and demographics of specific populations. However, surveys can also have drawbacks like non-response bias or unrepresentative sample sizes that may limit the generalizability of the results. In contrast, an impact assessment integrates various methods and data sources to present a comprehensive view of potential policy effects.