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In this section we try to provide some resources to assist with your research and your use of Stata. Many surveys are based on cluster samples rather than simple random samples. The traditional simple random sampling statistics must be adjusted to allow for the clustering. For an introduction to cluster sampling, illustrated using Stata, you can download a Word document on sampling (82kb). You can also download a PowerPoint introduction to sampling (75kb).

One of the modern psychometric procedures for scale development is item response theory (IRT) also known as Rasch analysis or latent trait scaling. You can download a PowerPoint introduction to item response theory (69kb).