The survey is an element of health data collection. The validity of the questionnaire is essential to achieve useful evidence, being a crucial aspect in identifying and correcting sources of bias during data collection. Verbal and cognitive tests are recognized as a tool to assess whether questions cause problems for both, the interviewer and the interviewee. The aim of this study was to validate the OHIP-49 and OHIP-19 instruments in a sample of Costa Ricans applying cognitive tests such as probing and thinkalouds and then a standard pretest. In a sample of 15 individuals rehabilitated with dentures a questionnaire of 42 items was applied that served as a cognitive test. Also 20 individuals performed a standard pretest using the telephone. The validation of this instrument served to determine the final sample for a further investigation and also to collect information about the duration of the survey as well as its comprehension.

Keywords: Cognitive interview, Verbal probing, Standard Pretest, Instrument validation, Patient satisfaction, Oral health survey