Abstract
Objective
The aim of this study was to develop a patient-based measure of the process and outcome of combined orthodontic and orthognathic care in the National Health Service in the UK.
Design
Identification of relevant dimensions through qualitative methods, design of form, determination of psychometric properties of the scale, specific readability, reliability and validity.
Setting
NHS hospitals in the South West Region.
Subjects
The sample comprised patients who had received combined orthodontic and orthognathic treatment between 01 January1998 and 31 December 2000. Twenty-six participants (a 25% response rate) took part in four focus group meetings. Thirty subjects (65% response rate) took part in a pilot study to test the properties of the questionnaire.
Main outcome measures
Six broad themes emerged from the focus groups. These formed the basis of the sections in the questionnaire.
Results
The questionnaire developed had a Flesch reading ease score of 72.9 or US grade level 4 equivalent to aged 9–10 years. Test–retest reliability gave kappa values for most questions that exceeded 0.4. Criterion validity of the measure was established by comparing responses to the questionnaire over two periods with a telephone interview on a sample of 30 patients. Criterion related validity was poor for nine of the 16 items. By contrast the construct validity of the questionnaire was satisfactory.
Conclusion
A patient-based measure of the process and outcome of combined orthodontic and orthognathic treatment has been developed. This has sufficient validity and reliability for use in inter-center audit projects.
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