An instrument calibrated by Item Response Theory to assess knowledge about head and neck cancer

ABSTRACT

Introduction: Head and neck tumors are in the 9º place among the most frequent cancers in the world, being the incidence of 700,000 new cases per year. To suspect and to diagnose early the cancer implies to know well the subject. The questionnaire is a good instrument for measuring knowledge. Objective: To provide an item bank, calibrated by the Item Response Theory (IRT), to evaluate the "knowledge about head and neck cancer", in any respondent, in order to benefit the studies on this construct, in the area of health education. Methods: To evaluate the "knowledge about head and neck cancer", we started with a scale already calibrated by the IRT, with 24 items for schoolchildren (n = 2,006). A further 29 items of equal difficulty were created (n = 994 schoolchildren). Then, 60 new items, of equal construct and greater difficulty (n = 883 dentistry professionals) were incorporated into this scale. Results: The analysis of 2,847 responses resulted in a bank with 113 items on head and neck cancer calibrated by IRT and arranged on a skill scale. Conclusion: From this collection of items, different questionnaires can be set up according to the skill level of the respondent. The results of the evaluations, in single or distinct moments, can be compared since the items are on the same scale of ability.