The Survey Quality Predictor (SQP) is: — an extensive open-access database of survey questions and quality estimates built up through the collaboration of the users. The SQP database contains a wide range of survey questions concerning many different topics in many different forms and languages.

— a tool for improving questions. By providing information about the quality of different question formats, the software can help design better questions. In this context, the quality of a survey question is defined as the strength of the relationship between the latent variable of interest and the response to the survey question, the observed variable. The quality can be computed by taking the product of reliability and validity.

The information provided by SQP is beneficial for: 1. Questionnaire Development (by consulting the SQP database, comparing and evaluating different question versions). 2. Translation Checks (by comparing the formal and linguistic codes between different language versions of the same question) 3. Correction for Measurement Error (by using the quality estimates in the substantive analyses)