WhatsApp Lifestyle Program — Structured Protocol
A ready-to-run script that replaces open-ended group chat with a structured behavior-change protocol: onboarding, daily/weekly check-ins, if-then planning prompts, cohort structure, and an honest measurement plan.
1. Program Structure
- Cohort size: 5–8 participants per group (not one large chat) — reduces social comparison and diffusion of responsibility.
- Two channels per cohort: a Data Log channel (structured prompts only) and a Cheer channel (peer encouragement) — keeps signal and noise separate.
- One moderator or bot per cohort sends prompts on schedule — participants never have to remember to check in.
- Program length: 8 weeks, with defined success metrics set before Day 1 (see Section 5).
2. Onboarding Message (Day 0)
Sent individually before the cohort chat opens:
"Welcome! This program runs for 8 weeks in a small group of 8. Each day you'll get one short check-in — just reply with a number or Y/N, no essays needed. Before we start, pick ONE if-then plan for this week (example below). We'll track [chosen metric] weekly and share group (not individual) progress every Friday."
Collect at onboarding (locks in the measurement plan):
- Baseline metric value (weight, step count, workouts/week — pick one primary metric)
- Chosen if-then plan for week 1
- Consent to weekly aggregate reporting
3. If-Then Plan Prompt (Day 0, repeated Day 1 of each week)
Sent as a fill-in-the-blank, not open discussion:
"If [specific time/situation], then I will [specific small action]."
- Example: "If it's 7:00am on a weekday, then I will walk for 10 minutes before checking my phone."
- Participants submit privately to the moderator, not the group — avoids performative commitments.
- Moderator reflects it back as a reminder at the trigger time where possible (scheduled message).
4. Daily / Weekly Check-In Templates
Daily (Data Log channel — 15 seconds to answer)
| Prompt sent | Expected reply format |
|---|
| Did you follow your if-then plan today? (Y/N) | Y or N |
| [Primary metric] today, if tracked (optional) | number or skip |
Weekly (Friday — Data Log channel)
| Prompt sent | Expected reply format |
|---|
| Primary metric this week | number |
| Days you followed your if-then plan (out of 7) | 0–7 |
| One thing that got in the way (optional) | short text |
| Update your if-then plan for next week? | keep or new plan |
Weekly (Cheer channel — Friday, after data log closes)
Moderator posts an aggregate, never individual call-outs:
"Group update: 6 of 8 logged this week, average adherence 5.1/7 days. Nice work — see you Monday."
Keeps encouragement social without shame-based comparison.
5. Success Metrics — Define Before Day 1
Pick one primary and one adherence metric up front. Example:
| Metric type | Example definition | Measured how |
|---|
| Primary outcome | 5% change in [weight / resting HR / steps] at 8 weeks | Weekly self-report, or connected tracker if available |
| Process / adherence | ≥5 of 7 if-then days completed per week | Daily Y/N reply |
| Engagement (secondary only) | % of cohort submitting weekly check-in | Auto-count of replies |
Important: engagement (messages sent, chat activity) is tracked but never reported as a success measure on its own — it's a diagnostic for dropout risk, not evidence the program works.
6. Avoiding the Survivorship-Bias Trap
- Report outcomes for everyone enrolled at Day 0, including anyone who stops responding (intention-to-treat) — not just active repliers.
- A non-reply for 2 consecutive weeks triggers Section 7 (re-engagement), not silent removal from the denominator.
- If comparing to a past cohort or a no-program baseline, stagger start dates (e.g., Cohort A starts this month, Cohort B next month) so you have a rough control for calendar effects.
- Final report format: "X of Y originally enrolled hit the target metric" — never "X% of active participants."
7. Attrition & Re-Engagement Plan
Dropout is expected and exponential by default — plan touchpoints rather than assuming one onboarding message is enough.
| Trigger | Action |
|---|
| Day 3 no reply | Moderator sends a 1-line personal check: "All good? No pressure, just checking in." |
| Day 14 low adherence (<2/7 days) | Offer to revise the if-then plan — it may be too ambitious |
| 2 consecutive missed weekly logs | Personal outreach; offer to pause/rejoin next cohort rather than silently drop |
| Day 30 | Mid-program review message + optional plan reset for the second half |
8. Weekly Moderator Checklist
- Mon: send/confirm if-then plan for the week
- Mon–Thu: send daily Y/N prompt; no follow-up needed on replies
- Fri: send weekly metric + adherence prompt (Data Log)
- Fri (after logs close): post aggregate summary (Cheer channel)
- Fri: flag anyone at 2+ consecutive missed logs for Section 7 outreach
- Every 4 weeks: report intention-to-treat progress against the Section 5 metric to whoever owns the program
9. One-Page Summary
Structured prompts (not open chat) → logged small if-then actions → visible weekly feedback (aggregate, not individual) → small cohorts (5–8) → honest measurement that counts everyone enrolled, including dropouts.
WhatsApp is just the delivery channel; the protocol above is the actual mechanism.