Three, seven-point Likert-type items are used to measure the degree to which the employee of a service provider was viewed as being sincere during an encounter. In the study by Winsted (1997), respondents were asked to think of a recent experience with a waiter or waitress in a restaurant.
The Marketing Scales Handbook is indispensible in identifying how constructs have been measured and the support for a measure's validity and reliability. I have used it since the beginning as a resource in my doctoral seminar and as an aid to my own research. An electronic version will make it even more accessible to researchers in Marketing and affiliated fields.