Table 1.
Final baseline survey sample size calculation
| Trial 1 | Trial 2 | Trial 3 | Trial 4 | |
|---|---|---|---|---|
| Duration of trial recruitment | 3.2 h | 7 days | 9 days | 32 days |
| Total # (N) of surveys accessed | 1252 | 4943 | 5412 | 5846 |
| Total # of surveys removed % (of N) | 30.0 (381) | 34.4 (1699) | 36.1 (1956) | 39.5 (2310) |
| # (n) Reasons for removal [% of n] | 381 | 1699 | 1956 | 2310 |
| Blank surveys | 1.0% (1) | 1.9% (33) | 1.9% (38) | 1.5% (34) |
| Duplicates and suspicious data a | 9.2% (35) | 11.8% (200) | 3.6% (71) | 9.5% (220) |
| Incomplete eligible screeners | 8.9% (34) | 2.8% (47) | 4.1% (81) | 5.4% (125) |
| Ineligible screeners b | 50.7% (193) | 54.3% (923) | 65.6% (1284) | 58.8% (1359) |
| Participants did not pass all attention checks | 27.8% (106) | 27.4% (466) | 22.1% (432) | 21.0% (485) |
| Participants who indicated they did not respond honestly | 2.4% (9) | 1.8% (30) | 2.6% (50) | 3.8% (87) |
| Final baseline survey sample size | 871 | 3244 | 3456 | 3536 |
a Participants who accessed the survey multiple times, but only submitted one complete survey were retained once in the final sample. Those who completed the entire survey more than once were considered to have provided suspicious data and are not included in the final sample size
b Ineligible screeners refers to those who did not proceed to the baseline survey (i.e. were <18 and reported consuming alcohol less than once per week)