Skip to content
Gamify It.
Connect

Technique · Hooked

A reminder tied to the plan the user chose

Let the user pick a goal and a time during setup, then send one reminder at that time that names their own plan and opens today's unit directly.

Evidence grade B. Moderate evidence: solid studies with some limits.StartReturn

Plain label: if-then reminder at a chosen timeAlso known as: implementation intention, if-then plan, plan reminder, time picker, scheduled reminder, commitment reminder

How it works

Deciding in advance when and where to act links a cue to the action, which raises follow-through. A reminder that echoes the user's own commitment also draws on the wish to stay consistent with it, and a deep link removes the step between the cue and the action.

What the research says

  • If-then plans showed a mean effect around d = 0.65 across 94 tests with more than 8,000 people.

    Gollwitzer & Sheeran, meta-analysis, 2006

How to build it

Mobile
Onboarding asks when the user will do it, with a time picker; the push names the plan and day ('Morning focus, day 4') and opens today's unit.
Web
Add to calendar with a link that opens the exact task.
B2B
Ask the team lead when the weekly review happens and post the reminder in that channel shortly before.
Email and SMS
One message at the chosen time with the day's unit inside it.

What can go wrong

  • A default time picked by the team, not the user.
  • A reminder that opens the home screen instead of the task.

Pairs well with

  • Add a no-guilt note for missed days.
  • Let what the user just completed schedule the next reminder.

In practice

Where it shows up

  • Duolingo · 2020

    Round

    Duolingo: smarter reminders, not more reminders

    The bandit algorithm lifted total DAU 0.5% and new-user retention 2% over a strong baseline, without sending more notifications (Yancey & Settles, KDD 2020; company authors, peer-reviewed).

    M4 ×Return
    Case grade for the number: A. Evidence grade for the mechanism link: B.

  • 24 Hour Fitness (megastudy) · 2021

    Round

    The gym megastudy: most effects didn't last

    54 interventions, 61,293 members of 24 Hour Fitness: 45% significantly raised weekly gym visits (by 9-27%) during the four-week programs; only 8% produced measurable change after they ended; impartial forecasters failed to pick the winners (Milkman et al., Nature, Dec 8, 2021).

    ReturnStay
    Case grade for the number: A. Evidence grade for the mechanism link: A.

  • YouVersion (Bible App) · 2025

    Round

    YouVersion: an ethical habit at a billion installs

    1 billion downloads across YouVersion's apps (announced in late Oct 2025, reported Nov 17, 2025), with installs up 12% YoY and daily usage up 18% (press). Book era: 100M downloads by July 2013 (Hooked, Ch7). Many causes.

    M4 ×Return
    Case grade for the number: C. Evidence grade for the mechanism link: D.Analyst inferenceCorrelational

Limits

What we don’t claim

  • The Hook Model is a practical design tool, not a validated or complete theory of behavior.Hooked, Introduction
  • Left Brain and Right Brain are a metaphor for extrinsic and intrinsic motivation, not a claim about neuroscience.Actionable Gamification Ch.13, pp.342-343
  • Habit metrics need the longer habit horizon (weeks to months) before they can be read.

Sources

  • Hooked · Nir Eyal

    Ch.7

  • Implementation intentions and goal achievement: a meta-analysis · Gollwitzer & Sheeran, Advances in Experimental Social Psychology, 2006

    Evidence grade B. Moderate evidence: solid studies with some limits.

Source IDs: HK-TRG31F21

Book content is paraphrased, never quoted at length. Last verified October 24, 2026.

Your product

Find the stage your product is stuck in

Gamify It reads your product, picks the one move that matters at its stage, and sizes the test to your traffic. Connecting is free; a Pro subscription starts it.

Add Gamify It to your assistantTake the 2-minute check-up