Understanding and Using Statistics in Psychology takes the fear out of psychological statistics to help students understand why statistics are carried out, how to choose the best test, how to carry out the tests, and then perform the analysis in SPSS. Emphasizing the place of statistical analysis in the process of conducting research, from design to report writing, this accessible and straightforward guide takes a non-technical approach, encouraging the reader to understand why a particular test is being used and what the results mean in the context of a psychological study. The focus is on meaning and understanding rather than numerical calculation.

Analysing Questionnaires and Measurement Instruments

Analysing questionnaires and measurement instruments

What's in This Chapter?

  • Reliability
  • Coefficient alpha
  • Cohen's kappa
  • Using SPSS

Key Terms

Bland-Altman limits of agreement


classical test theory

coefficient alpha

Cohen's kappa


Cronbach's alpha

internal consistency

line of best fit

line of equality



split-half method

standardised alpha

temporal stability

test-retest reliability

true measure



We live in a world that constantly surveys its population. Questionnaires are big business, and statisticians have developed ever increasingly sophisticated ways to analyse this wealth of data. Questionnaires are also the most common way of collecting data in applied areas of psychology. This chapter introduces some simple psychometric principles and techniques of analysis such as coefficient (Cronbach's) alpha, and other measures of reliability.


In psychology, we spend a great deal of our time measuring things, and a great deal of our time thinking about how to measure things. The ...

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