Retention Triangle
Cohort retention laid out as a triangle - each row a cohort, each column an age. The shape that reveals whether retention is improving and where it flattens.
- Term
- Retention triangle
- Rows
- Customer cohorts (by acquisition period)
- Columns
- Age — periods since acquisition
- Triangular because
- Recent cohorts have fewer observed periods
Forms & parts of speech
Definition in plain terms
A retention triangle is the standard way of laying out cohort retention data in a table. Each row represents a cohort - the group of customers or users acquired in a particular period, like a given month.
Each column represents an age, meaning the number of periods since that cohort was acquired (month 0, month 1, month 2, and so on). Each cell shows how much of that cohort was still retained at that age.
The table takes a triangular shape: the oldest cohort has many periods of observed data stretching across the row, while the most recent cohort has only one or two periods of data so far, because not enough time has passed.
Reading down a column compares the same age across cohorts; reading across a row follows one cohort as it ages. It's the foundational view for understanding retention honestly.
Why it matters to growth leaders
The retention triangle is one of the most important analytical tools a growth leader can use, because it reveals whether a business is actually getting healthier at its core.
Reading down an age column - say, month-3 retention across successive cohorts - shows whether newer cohorts are retaining better than older ones, which is the clearest signal that product, onboarding, or activation improvements are working.
Reading across a row shows the shape of a cohort's retention curve: whether it declines and flattens to a stable plateau (healthy) or decays toward zero (a leaky business).
Because the triangle separates the effect of a cohort's age from calendar-time effects, it cuts through the noise that blended retention numbers hide.
For a growth leader, the retention triangle is where you see the truth about whether growth is building a durable base of retained customers or pouring new users into a leaky bucket.
Laying out cohorts as rows and age (periods since acquisition) as columns, the triangle separates how a cohort retains as it ages from calendar-time effects that muddy a single blended figure.
Reading down the month-3 column - comparing the same age across successive cohorts - the leader sees newer cohorts retaining clearly better than older ones at the same age, the cleanest possible signal that the product and onboarding changes are improving real retention.
Reading across the rows, the cohorts' retention curves decline and then flatten to a stable plateau rather than decaying toward zero, the shape of a healthy, durable base. The triangular shape itself is expected - recent cohorts simply have fewer observed periods so far.
Using the retention triangle, the growth leader confirms with evidence what blended numbers couldn't show: the business is getting healthier at its core, building a retained base rather than pouring new users into a leaky bucket - and can keep investing in the changes that are working.
and missing whether curves flatten to a plateau or decay to zero.
Synonyms & antonyms
Synonyms
Antonyms
Origin & history
The retention triangle organizes cohort retention by cohort and age, taking a triangular shape from the limited observation of recent cohorts; it is the foundational view for separating age effects from calendar time and seeing whether retention is genuinely improving.
Etymology: source.
Usage trends
Search interest for this term over the last five years:
Common questions
- What is a retention triangle?
- A cohort-analysis table where each row is a cohort and each column is an age (periods since acquisition), showing retention as cohorts age; it's triangular because recent cohorts have fewer observed periods.
- How do you read a retention triangle?
- Down a column compares the same age across cohorts (are newer cohorts retaining better?); across a row follows one cohort's retention curve as it ages (does it flatten to a plateau or decay to zero?).
- Why is it shaped like a triangle?
- Because the oldest cohorts have many periods of observed data while the most recent cohorts have only a few, since not enough time has passed for later ages to be measured.
Related tools & calculators
Resources & people to follow
- referenceWikipedia — cohort analysis
- referenceProduct-analytics and growth practice
- referenceRGM analysis — the retention triangle reveals whether newer cohorts retain better and whether curves flatten to a plateau — the truth behind blended retention
Curated, non-competitor resources verified per term.
Related training
- moduleMarketing analytics
Disciplines
Areas of marketing where retention triangle is a core concern: