Questionnaires constitute the basis of every survey-based statistical measurement. They are by far the most important measurement instruments statisticians use to grasp the phenomena to be measured. Errors due to an insufficient questionnaire can hardly be compensated at later stages of the data collection process. Therefore, having systematic questionnaire design and testing procedures in place is vital for data quality, particularly for a minimisation of the measurement error.

Against this background, the Directors General of the members of the European Statistical System (ESS) stressed the importance of questionnaire design and testing in the European Statistics Code of Practice, endorsed in February 2005. Principle 8 of the Code states that “appropriate statistical procedures, implemented from data collection to data validation, must underpin quality statistics.” One of the indicators referring to this principle requires that “questionnaires are systematically tested prior to the data collection.”

Taking the Code of Practice as a starting point, this Recommended Practice Manual aims at further specifying the requirements of the Code of Practice. The Recommended Practice Manual is structured into two parts. 1) The Executive Summary of the Recommended Practices for Questionnaire Development and Testing in the European Statistical System summarises the requirements for questionnaire design and testing in the European Statistical System (ESS). At the same time it briefly presents tools and methods considered as appropriate. It finally contains recommendations on how to develop strategies towards questionnaire design and testing tailored to the requirements of specific statistics. 2) The Handbook of Recommended Practices for Questionnaire Development and Testing in the European Statistical System describes the methods and tools in detail and gives practical hints and recommendations for their application. Furthermore, it presents the theoretical background of the question-answer process and contains suggestions for further readings.

Custodian: Eurostat