Conclusion: Multi-channel invitation yields highest response rate. SMS alone outperforms email or in-app alone.
Multi-channel arm reached 50% response by Day 2; single-channel arms required 4-5 days to approach 50%.
-------------------------------------------------------------------------------- END OF REPORT ================================================================================ CP Invite Trial txt
-------------------------------------------------------------------------------- 1. OBJECTIVE -------------------------------------------------------------------------------- To evaluate the effectiveness of targeted invitation methods within a closed population (N=500) for a controlled trial. The primary endpoint is the response rate (acceptance to participate) within 7 days.
-------------------------------------------------------------------------------- 3. RESULTS -------------------------------------------------------------------------------- | Arm | Invites Sent | Responses (Day 1-7) | Response Rate | |---------------------|--------------|---------------------|---------------| | A (Email only) | 125 | 42 | 33.6% | | B (SMS only) | 125 | 61 | 48.8% | | C (In-app only) | 125 | 38 | 30.4% | | D (Multi-channel) | 125 | 89 | 71.2% | Arm A: p <
-------------------------------------------------------------------------------- 2. METHODOLOGY -------------------------------------------------------------------------------- 2.1 Population: Closed group (registered panel members, no new entries allowed). 2.2 Sample Size: 500 individuals. 2.3 Invitation Channels (randomized equally, n=125 per arm): - Arm A: Email only - Arm B: SMS only - Arm C: In-app notification only - Arm D: Multi-channel (email + SMS reminder after 48h) 2.4 Invitation Message (standardized): "You are invited to participate in a 10-min confidential survey. Click [link] to begin. Reward: $10 gift card upon completion." 2.5 Trial Period: 7 consecutive days.
-------------------------------------------------------------------------------- 7. LIMITATIONS -------------------------------------------------------------------------------- - Closed population may not generalize to open populations. - Incentive ($10) might increase response rates beyond typical real-world levels. - No testing of push notifications vs. in-app banners. - Trial length (7 days) may underestimate late responders. 0.001 (significant) - Arm B vs.
Average response rate across arms: 46.0%
-------------------------------------------------------------------------------- 4. STATISTICAL SIGNIFICANCE (Chi-square test) -------------------------------------------------------------------------------- - Arm D vs. Arm A: p < 0.001 (significant) - Arm D vs. Arm B: p = 0.002 (significant) - Arm D vs. Arm C: p < 0.001 (significant) - Arm B vs. Arm A: p = 0.021 (significant) - Arm B vs. Arm C: p = 0.004 (significant) - Arm A vs. Arm C: p = 0.612 (not significant)
-------------------------------------------------------------------------------- 6. RECOMMENDATIONS -------------------------------------------------------------------------------- - For closed populations, use multi-channel invitations (email + SMS reminder). - If resources are limited, prefer SMS over email or in-app messaging. - Avoid relying solely on in-app notifications due to low visibility. - Future trials should test timing optimization (e.g., send reminders at 24h instead of 48h).