Willingness to pay for periodontal therapy: development and testing of an instrument.
OBJECTIVE
The objective of this study was to develop and test the feasibility and validity of a willingness to pay (WTP) tool in a dental setting.


METHODS
A questionnaire measured individuals' preferences among alternative treatments for periodontal disease and the maximum they would be willing to pay for their treatment of choice in terms of dental insurance premiums. The questionnaire provides detailed information, in probabilistic terms, of the risks and benefits of treatment choices for moderate to advanced adult periodontitis. It was pilot tested on 23 periodontal patients and 18 dental school faculty and staff.


RESULTS
The majority (92.6%) felt the questionnaire was an accurate representation of treatments and outcomes, establishing face and content validity. In terms of construct validity, four hypotheses were tested: (1) manipulation of the outcomes of the preferred treatment led to a predictable shift in preferences for 38 subjects (92.7%); (2) although periodontal patients were not more likely to choose periodontal surgery than nonpatients (P = .14), those with a history of surgery were more likely to choose surgery again (P = .06); (3) WTP was positively related to income level (P = .05); and (4) subjects were willing to pay more for coverage for themselves than for others. Periodontal surgery was the preferred treatment for moderate to advanced periodontal disease, and was more strongly preferred than other choices (i.e., a higher WTP) for all income groups. The intraclass correlation coefficient for treatment preferences was 0.95 (P < .001) and the kappa for WTP was 0.78 (P < .001).


CONCLUSIONS
This pilot study supports some of the criteria concerning validity of the WTP questionnaire to measure preferences for alternative periodontal therapies. Further testing on larger samples is required to confirm these results.
Matthews
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DC
Division of Periodontics, Dalhousie University, Halifax, Nova Scotia B3H 3J5 Canada. debora.matthews@dal.ca
Birch
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S
Gafni
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A
DiCenso
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A
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002755:Choice Behavior; D003362:Cost-Benefit Analysis; D003777:Dental Prophylaxis / Q000523:psychology; D005240:Feasibility Studies; D005260:Female; D005382:Financing, Personal / Q000706:statistics & numerical data*; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019647:Oral Surgical Procedures / Q000523:psychology; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D010518:Periodontitis / Q000191:economics* / Q000628:therapy*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires