Psychometrics tutorial - General steps
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View the accompanying screencasts: [1] [2]
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Recommended psychometric instrument development steps emphasised in this tutorial are:
- Check and prepare the data
- Reverse code (if necessary) so that all variables are scored in the same direction
- Examine the univariate properties (e.g., histogram, mean, standard deviation, skewness, and kurtosis)
- Examine the bivariate properties (e.g., scatterplots and correlations) to help understand the data.
- Exploratory factor analysis
- Decide on a purpose and ask a research question
(e.g., what are the underlying dimensions of X?)
- Examine assumptions (sample size, linear relations, and factorability)
- Choose method of:
- Determine the number of factors
- Name and describe each factor
- Identify which items belong to each factor, drop problematic items as necessary, and repeat analysis
- Analyse internal consistency for each factor
- Examine correlations amongst the factors
- Compute composite scores (if needed)
- Check factor structure across sub-groups
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