Instrument validation process: a case study using the Paediatric Pain Knowledge and Attitudes Questionnaire

Aims and objectives To compare two methods of calculating interrater agreement while determining content validity of the Paediatric Pain Knowledge and Attitudes Questionnaire for use with Australian nurses. Background Paediatric pain assessment and management documentation was found to be suboptimal revealing a need to assess paediatric nurses' knowledge and attitude to pain. The Paediatric Pain Knowledge and Attitudes Questionnaire was selected as it had been reported as valid and reliable in the United Kingdom with student nurses. The questionnaire required content validity determination prior to use in the Australian context. Design A two phase process of expert review. Methods Ten paediatric nurses completed a relevancy rating of all 68 questionnaire items. In phase two, five pain experts reviewed the items of the questionnaire that scored an unacceptable item level content validity. Item and scale level content validity indices and intraclass correlation coefficients were calculated. Results In phase one, 31 items received an item level content validity index 0·90 and an intraclass correlation coefficient of 0·94 demonstrating excellent agreement between raters therefore acceptable content validity. Conclusion Equivalent outcomes were achieved using the content validity index and the intraclass correlation coefficient. Relevance to clinical practice To assess content validity the content validity index has the advantage of providing an item level score and is a simple calculation. The intraclass correlation coefficient requires statistical knowledge, or support, and has the advantage of accounting for the possibility of chance agreement.