Define activation without a slogan
A dated, falsifiable definition, with the exclusion list written beside it.
Cohort Instrumentation
Eight weeks on the cuts that make app analytics either trustworthy or ornamental. You finish with a workbook, a written activation definition, and a readout format Rowan still uses with paying clients.
Who it is for
Analysts and product leads who already have an event stream.
This is not an introduction to Mixpanel, Amplitude, or BigQuery. Those tools appear, but only as places where a bad cohort definition goes to look official. You should already be able to find an event, a user id, and a timestamp.
Typical seats: a product analyst in a UK marketplace, a growth lead in a regulated fintech, a founder who has outgrown “weekly active” as a religion. If your tracking plan is empty, take Event Taxonomy Studio first.
Time: about five hours in the week you do the homework properly, plus a ninety-minute clinic. Recordings exist; they are a poorer substitute.
What the eight weeks actually contain
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01
The lie in the default cohort
Vendor defaults that mix new and returning users, ignore timezone, and treat uninstall as silence. You rebuild the first cut by hand.
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02
Activation as a dated claim
Writing the sentence “a user is activated when…” so that it can survive legal, finance, and a new CPO. Windows, not vibes.
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03
Exclusion logic
Internal testers, staff accounts, refunded trials, and the quiet British habit of using a personal device as a staging phone.
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04
Calendar and acquisition weather
Bank holidays, payday, App Store featuring, and paid campaigns that make D7 look like a product miracle for nine days.
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05
Holdouts you can explain
When a cohort comparison is an experiment in disguise. Minimum detectable effects without pretending you have Silicon Valley volume.
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06
The one-page readout
Claim, caveat, next instrument. Practised on the studio’s anonymised UK consumer set, then on your own stream if counsel allows.
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07
Handover
How the definition lives in a tracking constitution rather than in one analyst’s head. A short oral exam with Rowan.
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08
Repair week
You bring a broken chart from work. The room helps. This week is why people stay for Cartograph rather than Survey Desk alone.
Learning outcomes
Spot a cosmetic cohort
You will recognise the five default settings that make retention look kinder than the product deserves.
Write for a mixed room
A brief that a designer, a CFO, and an engineer can all annotate without a glossary slide.
Leave a constitution
The next analyst can add a property without summoning you from the Lakes.
Rowan Calder
Rowan spent nine years as head of measurement at a Manchester payments group, then two as an advisor to NHS-adjacent consumer apps. They founded the Otterburn studio in 2015 after noticing that vendor certifications taught clicks, not claims. Rowan still takes five Meridian seats a year and tutors every Cartograph cohort of Cohort Instrumentation.
How this programme is offered
There is no checkout on this site. Fees below describe the coming season. Enrolment is confirmed by email after a short fit conversation.
Survey Desk
£640
Self-paced materials from the last Cartograph run. No clinic seat. Suitable if your diary cannot take Thursdays.
Cartograph Studio
£1,920
Eight clinics, the workbook, and repair week. Twelve seats. This is the version described in the modules above.
Meridian Atelier
£4,150
Cartograph plus five private hours with Rowan against your own event stream. Five seats a year.
See the full fees page for what is included across the studio, and refunds for the cooling-off rules.
“Repair week is the reason I paid Cartograph prices. We brought a broken onboarding cohort from our building society app and left with an exclusion list legal would actually sign.”
“I wanted vendor shortcuts. Rowan would not give them. Fair, though I found week four slow if you already live in SQL.”
★★★★★
“The activation sentence is now in our tracking constitution. New PMs hate it, which is how I know it is working.”
Before you write
Will this teach me Amplitude from scratch?
No. Cohort Instrumentation assumes you already have an event stream and can click through a vendor or a warehouse. We will not walk through account setup, billing, or the marketing site of any analytics company. If you need naming discipline first, take Event Taxonomy Studio. If you need vocabulary, take the Signal Desk Primer.
Can I use my employer’s data?
Yes, when your counsel agrees. Meridian Atelier is designed for that. Cartograph Studio defaults to the anonymised UK consumer set so that twelve people can argue about the same table.
Is there a certificate?
You receive a letter confirming completion of the clinics you attended. We do not sell framed badges. Employers who know the studio ask for the workbook instead.
What if I miss a Thursday?
Recordings are issued within a day. They are useful. They are not the same as having Rowan interrupt your funnel live. Two absences are common; four usually means Survey Desk would have been the kinder purchase.