Methods: experiments (psychology), ethnography (anthropology), statistical modeling (economics, sociology).
Tools: surveys, interviews, psychological testing, big data.
Flaws: researcher bias, sample limitations, self-reporting errors, observer effects (people behave differently when observed).
Why flaws matter: If flawed tools are used, policies based on research can harm people.
Example: The Stanford Prison Experiment → method flawed by lack of controls and researcher influence, yet it shaped public perceptions of authority and ethics.