With significant new and updated content, the second edition of the indispensable APA Handbook of Research Methods in Psychology features descriptions of techniques that psychologists and others have developed to pursue a shared understanding of why humans think, feel, and behave the way they do. Chapters address the philosophical, ethical, and societal underpinnings of psychological research; the research planning process; measurement techniques; aspects of quantitative, qualitative, neuropsychological, and biological research designs; techniques for data analysis; and issues in writing up research.