When pretesting, ask your testers to fill out the instrument in the same manner in which you anticipate collecting the data, i.e., if you plan a telephone survey, personal interviews or mail survey, then pretest over the telephone, in an interview setting or have people fill out the questionnaire without assistance. After the test group has completed the instrument, ask if there were any questions they did not understand. In an effort to avoid looking stupid, respondents may fill out a question even if they do not understand it. Also check to see if the response categories are appro priate. Sometimes you will need to add another category or revise the wording of possible responses.
Quality is more important than size.
The goal of sampling is to obtain responses from representatives of the entire population of interest. Simply interviewing friends or those who only shop on Saturdays will probably not result in reliable data. Those not interviewed may differ from those interviewed. Consult a marketing research text for more information on sampling designs. Data Collection Data collection typically involves supervising those collecting the data.