From Research Methods in Psychology

[edit] STUDYING THIS CHAPTER WILL HELP YOU TO

• UNDERSTAND THE PROBLEMS OF MEASUREMENT IN PSYCHOLOGY.
• UNDERSTAND WAYS OF DESCRIBING MEASURES IN TERMS OF THEIR LEVEL OF MEASUREMENT.
• UNDERSTAND THE IMPORTANCE OF RELIABILITY AND VALIDITY IN PSYCHOLOGICAL MEASUREMENT.
• BE DIFFERENT WITH, AND BE ABLE TO EVALUATE, DIFFERENT METHODS OF DATA COLLECTION

[edit] Why do you need to know this?

Why do we have a chapter on measurement? We have a whole chapter on ‘Measurement in Psychology.’ Why a whole chapter on measurement? Because measurement in psychology has special difficulties, and is a special subject in itself. The branch of psychology associated with measurement is known as ‘psychometrics’ and it is a large and important area of psychological research. There are several academic journals devoted to the subject (Psychometrika, Applied Psychological Measurement, Educational and Psychological Measurement), and many advanced courses in psychology contain a module on psychometric theory. When you design your research projects, you need to think long and hard about how to measure the construct (thing) that you are interested in. It is very easy to think that you are measuring something well, and then find that what you really measured was completely different.

[edit] CRUCIAL CONCEPTS

PSYCHOMETRICS; LEVELS OF MEASUREMENT; NOMINAL, ORDINAL, INTERVAL AND RATIO SCALES; RELIABILITY; INTERNAL CONSISTENCY; VALIDITY; QUESTIONNAIRE; INTERVIEW; OBSERVATION REACTIVITY; ETHICS; SELF-REPORT; QUESTIONNAIRE; INTERVIEW; SURVEY; OBSERVATION; PHYSIOLOGICAL MEASURES;