An introduction to the basic principles of psychological research (both experimental and non-experimental) with new coverage of qualitative research. Known for its readability, Experimental Methodology is organized so that each chapter focuses on a specific step in the research process. The primary orientation of this text is toward providing instruction in the experimental approach, but an introduction to non-experimental approaches such as ex-post facto research, correlational research, and survey research is provided. Rather than dichotomizing psychological research into descriptive and experimental research, this edition takes the more current approach of using the quantitative and qualitative research dichotomy, presented in Chapter 2. Christensen also contains strong coverage of research ethics. Experimental Methodology can be accompanied by a lab manual.