FIELD TESTING OF ALL QUESTIONS, SURVEY INSTRUMENTS AND PROCEDURES WAS CONDUCTED AMONG 30 NAKHONSAWAN RESIDENTS WHO HAD BEEN SELECTED THROUGH CONVENIENCE SAMPLING AND VARIED IN AGE AND GENDER. SOME ADJUSTMENTS OF THE QUESTIONNAIRE, SUCH AS WORDING, QUESTION STRUCTURE
AND QUESTION ORDER WERE MADE AFTER THE FIELD TEST. MOST ITEMS HAD BEEN PREVIOUSLY TESTED AND USED IN THE SENTINEL SURVEILLANCE OR IN OTHER RESEARCH PROJECTS IN THAILAND