Pressure ulcer prevention: development and psychometric validation of a knowledge assessment instrument

Abstract

Background: Profound knowledge of pressure ulcers is important to enable good prevention. Validity and reliability of instruments assessing pressure ulcer knowledge are limited evaluated in previous research.

Aims and objectives: To develop a valid and reliable instrument to assess knowledge of pressure ulcer prevention.

Design: Prospective psychometric instrument validation study.

Methods: An extensive literature review was performed to develop an instrument to assess knowledge of pressure ulcer prevention. Face and content validity were evaluated in a double Delphi procedure by an expert panel of nine trustees of the European Pressure Ulcer Advisory Panel (EPUAP) who each have extensive experience in pressure ulcer care and research (PhD level). A convenience sample of 608 nurses and nursing students from Belgium and The Netherlands participated to evaluate validity of the multiple-choice test items (item difficulty, discriminating index, quality of the response alternatives), construct validity, internal consistency, and stability of the instrument. The data were collected between February and May 2008.

Results: A 26-item instrument was developed, reflecting 6 themes expressing the most relevant aspects of pressure ulcer prevention. The content validity was excellent (CVI=0.78-1.00). Group scores of nurses with a (theoretically expected) high level of expertise were found to be statistically significantly higher than those of participants with (theoretically expected) less expertise (P<0.001). The item difficulty index of the questions ranged from 0.27 to 0.87, while values for item discrimination ranged from 0.29 to 0.65. The quality of the response alternatives was found to be good. The overall internal consistency reliability (Cronbach's alpha) was 0.77. The 1-week test-retest intraclass correlation coefficient (stability) was 0.88.

Conclusion: The instrument demonstrated acceptable psychometric properties and can be applied in both research and practice for evaluating knowledge about pressure ulcer prevention.