We recommend at least 12 participants for pilot studies with primary focus of estimating average values and variability for planning larger subsequent studies. This size is quite practical for most early‐stage investigators to conduct within single centers while still providing valuable preliminary information.

The rule of thumb is to test the survey on at least 12 to 50 people prior to pilot testing or full-scale administration (Sheatsley 1983; Sudman 1983). This is a cost-, energy-, and time efficient number of people a large enough number that many will note the same problems with the sur- vey questions.

Thank You Getasew! for the clarification.

Hi Daniel,

1. Based on Wu, J. J. (2004). Influence of market orientation and strategy on travel industry performance: an empirical study of e-commerce in Taiwan. Tourism Management, 25(3), 357-365. This study distributed 600 questionnaires, Pretest 5 experts, Pilot test 25

2. According to Su, L., Swanson, S. R., & Chen, X. (2016). The effects of perceived service quality on repurchase intentions and subjective well-being of Chinese tourists: The mediating role of relationship quality. Tourism Management, 52, 82-95. This study distributed 600 questionnaires, Pretest 7 experts, Pilot test 50

3. Based on Bradburn, N. M., Sudman, S., & Wansink, B. (2004). Asking questions: the definitive guide to questionnaire design--for market research, political polls, and social and health questionnaires. John Wiley & Sons. Pilot test should be at least from 10-12 participants.

Dear Zakaria Elkhwesky Sir,

You are absolutely correct....Pretest required 4 -8 experts, Pilot test of 50 respondents.... required as minimum number of respondents to conduct a pilot survey...... Thank you sir for sharing your views

"An audit of sample sizes for pilot and feasibility trials being undertaken in the United Kingdom registered in the United Kingdom Clinical Research Network database"

Thank you all!

Depends on type of study but in an average 50-60 samples is sufficient to conduct pilot studies.