How to find your activation metric (aha moment) in data

Maya

The onboarding team wants one goal for new users: the moment Halves clicks. Which action in the first week makes people stay?

Alex Tutor

We're looking for an activation criterion: the moment a new user first gets the core value, written as an action plus a time limit. “Added three expenses in week 1”, not “got it”.

The method: take candidate actions, split users into those who did each one in week 1 and those who didn't, and compare how many are still around later. We'll use “opened the app on days 21–27”, week 4.

You

Then only the July cohorts work. Everyone who signed up after 2 August hasn't reached week 4 yet.

Alex Tutor

Right, that's why active_week4 is empty for them. Same file as before; use the 96 rows where it's filled.

Alex Tutor

Dataset · 192 rows

Halves new users, 6 July – 30 August 2026

192 sign-ups, data pulled on 31 August. `active_week4` is filled for the 96 July sign-ups.

Download CSV

Columns
user_id: User id
signup_date: Sign-up date (UTC); day 0
platform: ios or android
channel: invite (joined someone's group), app_store_search or paid_social
group_created_day: Day after sign-up the user created their first group; invitees never do
member_invited_day: Day the user sent their first invite
invite_accepted_day: Day someone first accepted the user's invite
first_expense_day: Day of the user's first expense
expenses_week1: Expenses the user added on days 0–6; empty if week 1 isn't over
active_week4: Opened the app on days 21–27 (true/false); filled only for sign-ups 6 July – 2 August

Data

user_id	signup_date	platform	channel	group_created_day	member_invited_day	invite_accepted_day	first_expense_day	expenses_week1	active_week4
m3u001	2026-07-06	ios	invite		5	7		0	true
m3u002	2026-07-06	ios	app_store_search	0	3	3	3	5	false
m3u003	2026-07-06	android	app_store_search	0	0	0	0	2	false
m3u004	2026-07-06	android	invite				4	5	true
m3u005	2026-07-06	ios	invite				11	0	true

Show 187 more rows

m3u006	2026-07-07	ios	paid_social					0	false
m3u007	2026-07-07	ios	app_store_search	0	0			0	false
m3u008	2026-07-07	android	paid_social					0	false
m3u009	2026-07-08	android	app_store_search	0	0		10	0	false
m3u010	2026-07-08	android	invite				13	0	false
m3u011	2026-07-08	ios	invite				5	6	true
m3u012	2026-07-08	android	app_store_search	0			5	2	false
m3u013	2026-07-09	ios	paid_social	0	0	0		0	false
m3u014	2026-07-09	android	paid_social	0	3		6	4	false
m3u015	2026-07-09	android	app_store_search	6	12			0	false
m3u016	2026-07-09	ios	app_store_search	0				0	false
m3u017	2026-07-10	ios	app_store_search	0	6	7	11	0	false
m3u018	2026-07-10	android	app_store_search	0			4	1	false
m3u019	2026-07-11	ios	invite				12	0	true
m3u020	2026-07-11	android	paid_social	5			11	0	false
m3u021	2026-07-11	ios	invite				0	6	true
m3u022	2026-07-11	ios	app_store_search	3	7	10	11	0	false
m3u023	2026-07-12	ios	app_store_search	0	2			0	false
m3u024	2026-07-12	android	invite				2	9	true
m3u025	2026-07-13	android	paid_social	0				0	false
m3u026	2026-07-13	android	paid_social	0	0	3	3	6	true
m3u027	2026-07-13	ios	app_store_search					0	false
m3u028	2026-07-14	android	app_store_search	0	0		5	1	false
m3u029	2026-07-14	ios	app_store_search	0	0	0	0	4	true
m3u030	2026-07-14	ios	paid_social	0				0	false
m3u031	2026-07-15	android	invite		3		5	8	true
m3u032	2026-07-15	android	app_store_search	0				0	false
m3u033	2026-07-15	ios	invite		1		1	7	true
m3u034	2026-07-15	android	paid_social	0	6			0	false
m3u035	2026-07-16	ios	app_store_search	0			5	1	false
m3u036	2026-07-16	android	invite				4	3	true
m3u037	2026-07-17	ios	invite				9	0	false
m3u038	2026-07-17	android	app_store_search	6	6			0	false
m3u039	2026-07-17	ios	app_store_search	0	0	2	4	4	true
m3u040	2026-07-18	ios	invite				0	8	true
m3u041	2026-07-18	android	paid_social	0	1	1	4	4	true
m3u042	2026-07-18	ios	invite				3	9	false
m3u043	2026-07-18	android	paid_social	0	2		0	3	true
m3u044	2026-07-19	ios	paid_social	0				0	false
m3u045	2026-07-19	ios	app_store_search					0	false
m3u046	2026-07-19	ios	paid_social	6				0	false
m3u047	2026-07-19	android	paid_social	0	1	1	3	4	true
m3u048	2026-07-19	ios	paid_social	6				0	false
m3u049	2026-07-20	android	app_store_search	0	0		10	0	false
m3u050	2026-07-20	ios	paid_social	0	0	0	3	9	true
m3u051	2026-07-20	ios	paid_social	0			6	4	false
m3u052	2026-07-20	ios	paid_social	2	2	2	3	4	true
m3u053	2026-07-20	android	invite				6	1	false
m3u054	2026-07-21	ios	app_store_search	0				0	false
m3u055	2026-07-21	ios	app_store_search	0	0	0	2	1	false
m3u056	2026-07-21	ios	app_store_search	0	5	5	9	0	false
m3u057	2026-07-22	android	paid_social	1	1	4	8	0	true
m3u058	2026-07-22	ios	invite				7	0	false
m3u059	2026-07-22	ios	invite				2	4	true
m3u060	2026-07-22	android	app_store_search	0	0			0	true
m3u061	2026-07-22	ios	invite				5	3	true
m3u062	2026-07-23	android	invite				5	1	false
m3u063	2026-07-23	ios	paid_social	0	0	1	5	5	false
m3u064	2026-07-23	android	paid_social	0	5		8	0	false
m3u065	2026-07-23	ios	app_store_search	0	4	4	5	7	false
m3u066	2026-07-25	ios	invite				2	1	true
m3u067	2026-07-25	ios	paid_social	3	4	4	7	0	false
m3u068	2026-07-25	android	paid_social	0				0	false
m3u069	2026-07-25	android	app_store_search	0	0		5	2	false
m3u070	2026-07-26	ios	paid_social	0	3	3	7	0	true
m3u071	2026-07-26	android	paid_social					0	false
m3u072	2026-07-26	android	app_store_search	0			0	2	true
m3u073	2026-07-27	android	invite		2		3	8	true
m3u074	2026-07-27	ios	app_store_search	0	1			0	false
m3u075	2026-07-27	ios	app_store_search	0			4	4	false
m3u076	2026-07-27	android	app_store_search	0				0	false
m3u077	2026-07-27	ios	invite					0	true
m3u078	2026-07-27	android	invite				11	0	true
m3u079	2026-07-28	ios	app_store_search	0	0	2	5	3	false
m3u080	2026-07-29	ios	invite				6	1	true
m3u081	2026-07-29	ios	invite				3	1	false
m3u082	2026-07-29	ios	invite		4	5	0	1	false
m3u083	2026-07-29	android	app_store_search	0	0	0	4	1	true
m3u084	2026-07-30	android	paid_social	0	2			0	false
m3u085	2026-07-30	ios	paid_social	5	5			0	false
m3u086	2026-07-30	android	app_store_search	8			16	0	false
m3u087	2026-07-31	ios	app_store_search	0	1	3	4	6	true
m3u088	2026-07-31	android	paid_social	0	5			0	false
m3u089	2026-07-31	ios	paid_social	0	0	0	3	1	false
m3u090	2026-08-01	ios	paid_social	0	0		3	1	false
m3u091	2026-08-01	android	paid_social					0	false
m3u092	2026-08-02	ios	app_store_search	0	3	6	10	0	false
m3u093	2026-08-02	ios	invite					0	false
m3u094	2026-08-02	android	app_store_search	1	1			0	false
m3u095	2026-08-02	ios	paid_social	2	2	5	8	0	false
m3u096	2026-08-02	android	app_store_search	0	0	0	3	5	true
m3u097	2026-08-03	ios	app_store_search	0	0	0	1	3
m3u098	2026-08-03	ios	invite				10	0
m3u099	2026-08-03	android	paid_social					0
m3u100	2026-08-03	android	app_store_search	0	0	0	0	8
m3u101	2026-08-03	android	paid_social	0				0
m3u102	2026-08-05	ios	app_store_search					0
m3u103	2026-08-05	ios	app_store_search					0
m3u104	2026-08-05	ios	app_store_search	0				0
m3u105	2026-08-06	android	invite				5	9
m3u106	2026-08-06	android	paid_social	1	5		4	4
m3u107	2026-08-06	android	paid_social	0	1	2	3	4
m3u108	2026-08-06	android	paid_social					0
m3u109	2026-08-06	ios	paid_social					0
m3u110	2026-08-07	ios	app_store_search	0	0	2	6	9
m3u111	2026-08-07	ios	paid_social	0	0			0
m3u112	2026-08-08	android	app_store_search	0	0		2	3
m3u113	2026-08-08	android	paid_social	0	0		9	0
m3u114	2026-08-08	android	paid_social	8			18	0
m3u115	2026-08-09	ios	app_store_search					0
m3u116	2026-08-09	ios	app_store_search	0				0
m3u117	2026-08-09	ios	paid_social	0	0	0	2	8
m3u118	2026-08-09	ios	invite				1	9
m3u119	2026-08-09	ios	app_store_search	0			8	0
m3u120	2026-08-09	ios	invite				4	6
m3u121	2026-08-10	ios	paid_social	0	0	0	4	8
m3u122	2026-08-10	ios	paid_social	0	0	0	0	5
m3u123	2026-08-11	android	invite				0	9
m3u124	2026-08-11	ios	app_store_search	7				0
m3u125	2026-08-12	ios	app_store_search					0
m3u126	2026-08-12	android	paid_social	0	1	1	3	2
m3u127	2026-08-12	android	paid_social	0			5	3
m3u128	2026-08-12	android	invite				0	9
m3u129	2026-08-12	android	app_store_search	0	0		2	4
m3u130	2026-08-13	android	app_store_search	0	0			0
m3u131	2026-08-13	android	app_store_search	0	2			0
m3u132	2026-08-13	ios	invite		2	4		0
m3u133	2026-08-14	android	invite					0
m3u134	2026-08-14	android	invite		2		0	4
m3u135	2026-08-14	android	app_store_search	0	2			0
m3u136	2026-08-14	android	app_store_search	0	0	0	1	1
m3u137	2026-08-14	android	app_store_search	0			5	3
m3u138	2026-08-15	ios	paid_social					0
m3u139	2026-08-15	android	invite				3	6
m3u140	2026-08-15	android	paid_social	0	0			0
m3u141	2026-08-15	android	invite				0	9
m3u142	2026-08-15	android	paid_social	2	5	8	12	0
m3u143	2026-08-16	ios	invite				1	4
m3u144	2026-08-16	ios	app_store_search	0	6	6	9	0
m3u145	2026-08-17	ios	invite				6	1
m3u146	2026-08-17	ios	app_store_search	0			9	0
m3u147	2026-08-17	android	paid_social	0			1	3
m3u148	2026-08-17	android	invite		6		4	5
m3u149	2026-08-18	android	app_store_search	0	0			0
m3u150	2026-08-19	android	invite				5	8
m3u151	2026-08-19	ios	app_store_search	9			10	0
m3u152	2026-08-19	ios	app_store_search	0				0
m3u153	2026-08-19	android	app_store_search	8	8	8	9	0
m3u154	2026-08-20	android	invite				3	5
m3u155	2026-08-20	android	app_store_search	0	0			0
m3u156	2026-08-21	ios	app_store_search	0				0
m3u157	2026-08-21	android	app_store_search	1	1		1	2
m3u158	2026-08-21	android	invite				1	1
m3u159	2026-08-21	android	invite				1	7
m3u160	2026-08-22	android	paid_social	0	1			0
m3u161	2026-08-22	ios	app_store_search	0	0	2	6	7
m3u162	2026-08-22	ios	app_store_search	0	0	0	3	6
m3u163	2026-08-22	ios	invite				1	5
m3u164	2026-08-22	ios	invite				0	7
m3u165	2026-08-23	ios	paid_social	0	0	0	2	6
m3u166	2026-08-23	ios	invite					0
m3u167	2026-08-23	ios	app_store_search	0	2			0
m3u168	2026-08-23	ios	invite				1	5
m3u169	2026-08-24	ios	app_store_search	0	0	3	5	7
m3u170	2026-08-24	ios	paid_social					0
m3u171	2026-08-24	android	app_store_search	0	0			0
m3u172	2026-08-24	android	paid_social	1	1		3	1
m3u173	2026-08-25	ios	invite
m3u174	2026-08-25	ios	app_store_search	0	3	3	5
m3u175	2026-08-25	android	invite		1
m3u176	2026-08-25	android	app_store_search	0			2
m3u177	2026-08-25	ios	paid_social	0
m3u178	2026-08-26	ios	invite				0
m3u179	2026-08-26	ios	app_store_search	0	3	3
m3u180	2026-08-27	ios	paid_social	0
m3u181	2026-08-27	android	invite				3
m3u182	2026-08-27	android	app_store_search	0
m3u183	2026-08-27	android	app_store_search	0	0	0	2
m3u184	2026-08-27	ios	invite
m3u185	2026-08-28	ios	paid_social	0	0
m3u186	2026-08-28	ios	app_store_search
m3u187	2026-08-28	ios	invite
m3u188	2026-08-29	android	paid_social	0
m3u189	2026-08-29	android	paid_social
m3u190	2026-08-29	ios	invite
m3u191	2026-08-29	ios	invite
m3u192	2026-08-29	ios	paid_social	0	0

Alex Tutor

Question 1

Among the 96 July sign-ups (rows with active_week4 filled), what share was active in week 4? In %, one decimal.

Your answer

Units: % (e.g. 45.5)

Alex Tutor

34.4% is the baseline. Now three candidates, each within days 0–6: A, a first expense; B, a second member in the group (someone accepted their invite, or they joined through one); C, at least three expenses.

A first: those with a first expense in week 1 kept 54.3% in week 4, those without only 16.0%. A gap of 38 points.

You

For B, a user counts if channel is invite or invite_accepted_day is 6 or less.

Alex Tutor

Question 2

Candidate B: users who had a second member in their group by day 6 (channel = invite, or invite_accepted_day ≤ 6). What share of them was active in week 4? July sign-ups only; in %, one decimal.

Your answer

Units: % (e.g. 45.5)

58.8% against 6.7% for those who never got a second member. And C, three or more expenses: 72.4% against 17.9%.

Maya

B is about the group, C is about using it. What if we need both?

Alex Tutor

Try it: users who had a second member and at least three expenses by day 6.

Alex Tutor

Question 3

Combined candidate: B and at least 3 expenses in week 1 (expenses_week1 ≥ 3). What share of July users who did both was active in week 4? In %, one decimal.

Your answer

Units: % (e.g. 45.5)

80.0% against 18.3%: the best separation so far. The catch is reach: only 25 of 96 users, 26%, got there. A criterion that almost nobody meets is a poor target for onboarding.

You

Though 26% is also the room to grow. B alone reaches 51 users, but its gap is smaller.

Maya

Before I pick the sharpest or the broadest, rank them for me.

Alex Tutor

Question 4

Order the candidates by the retention gap (did minus didn't, in points), largest first.

Tap an item, then tap where it should go. You can also drag or use the arrows.

Theo

Then it's simple. We push every new user to get a friend in and add three expenses, and week-4 retention goes to 80%.

Alex Tutor

That's the trap. Nobody assigned these users to do the action; they chose to. People who choose it can differ in ways that make them stay anyway. That's selection bias.

Look at invitees. They came because a friend already uses Halves with them. 44% of them reached the combined action, against 19% of self-signups. And invitees who didn't reach it still kept 46.7% in week 4; self-signups who didn't kept 10.7%.

You

So part of the 80% is just who those people are. Pushing a solo user through the same steps won't give them a friend who already wants to split bills.

Alex Tutor

Question 5

Why can't Theo promise 80% week-4 retention by pushing every new user to the combined action?

Choose one answerBecause 25 users is too few to compute a percentageBecause users chose the action themselves, and those who choose it, like invitees, would retain better anywayBecause week 4 is too early to measure retentionBecause the action has no link to retention at all

Maya

So is the analysis useless?

Alex Tutor

Not at all. It gives a strong candidate and a reason to believe in it. Within self-signups alone the gap still holds: 69.2% against 10.7%, on only 13 users who did it. To know whether pushing people there causes retention, test an onboarding change against a control group.

Maya

Then write me the activation criterion for the onboarding team, with the honest caveat.

Alex Tutor

Question 6Short answer · AI-checked task

Write the activation criterion for the Halves onboarding team in 3–5 sentences: the action and time limit, the evidence from the July data, and the caveat about what the data can't prove.

Write your answer and get a score with feedback from our AI reviewer.

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Alex Tutor

Find the moment in the data, then prove it with a test. Skipping the second step is how teams build onboarding around a coincidence.

Alex Tutor

That’s the lesson. You answered every task — nicely done.

Next lesson: Case: fix the onboarding funnel