Chapter 2 introduces us to the sources of personality data, to the means of evaluating personality measures, and to research designs in personality.

The authors first address the four primary sources of data collected by personality psychologists. These are self-report data (S-data), observer report data (O-data), Test-data (T-data), and life-outcome data (L-data). The authors then address the conditions under which links are and are not expected among data collected from the different sources. Because personality data are fallible, the authors recommend collecting data from more than one data source. Results that transcend data sources are more powerful.

The authors then discuss how personality measures are evaluated. This section of the chapter includes discussions of a measure's reliability, validity, and generalizability.

Next the authors discuss the three key research methods used by personality psychologists. These are experimental designs, correlational designs, and case studies. Each research method has strengths and weaknesses. The strength of one design is a weakness of another, and the weakness of one design is a strength of another. The authors note that the type of design one uses will depend on the research question and the purpose of the investigation.

Finally, the authors close by noting that no source of data is perfect and that no research method is perfect. Whether a data source or method is appropriate will depend on the research question and the purpose of the research.