Establishing reliability and validity of a constipation risk assessment scale

Introduction: Constipation presents as a predominant problem within health care, particularly within oncology. Previous publications have reviewed the literature and identified risk factors for constipation. Subsequently a constipation risk assessment scale was developed and subjected to content and face validity analysis. Study purpose: The primary purpose of this paper was to test the reliability of the instrument and further assess the validity of this tool. Reliability analysis: Tests for stability, equivalence and internal consistently demonstrated that the tool was stable over the passage of time, provided equivalent results when different raters used the tool and that the scale was homogenous. Validity analysis: Content and face validity analysis had been performed and outlined in a previous paper. Construct validity was established by contrasting constipated and non- constipated subjects. Subsequently a convenience sample of patients attending for their first cancer treatment, determined the predictive value of the tool. Concurrent validity was established by comparing nurses' judgements on subjects' risk of constipation to the category of risk given to each subject by the tool. Conclusion: This research has developed a reliable and valid instrument for constipation risk assessment for use in clinical practice. Ultimately this research extended theory on constipation to the predictive level and produced a comprehensive quantifiable method for assessing risk of constipation. (C) 2008 Elsevier Ltd. All rights reserved.