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ВопросЛегкаяbusiness-metricsВопрос по метрикам на скрининге · AdaptyAdapty

Расчет годового LTV подписки по retention curve

Расчет годового LTV подписки по retention curve

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Сначала сформулируйте ответ как на собеседовании, затем откройте разбор и оцените себя.

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Короткий ответ

Annual LTV is expected revenue over 12 months: 10 multiplied by the sum of monthly active-paying shares. Here it is about 37.38 dollars.

Полный разбор

Treat each monthly retention percentage as the expected fraction of the original cohort that pays in that month. The first four shares are 1, 0.5, 0.4 and 0.3.

From month 5 onward the share is multiplied by 0.9 each month, so the tail through month 12 is:

0.3⋅0.9+0.3⋅0.92+…+0.3⋅0.980.3 \cdot 0.9 + 0.3 \cdot 0.9^2 + \ldots + 0.3 \cdot 0.9^8

The annual LTV is:

10⋅(1+0.5+0.4+0.3+0.3⋅0.9⋅1−0.981−0.9)≈37.3810 \cdot (1 + 0.5 + 0.4 + 0.3 + 0.3 \cdot 0.9 \cdot \frac{1 - 0.9^8}{1 - 0.9}) \approx 37.38

The common sanity check is scale: a 10-dollar monthly subscription cannot produce a plausible one-year LTV of hundreds of dollars under these retention rates.

Теория

Subscription LTV from a retention curve is the price per period times the expected number of paid periods per starting user.

Типичные ошибки

  • Forget to convert percentages to fractions.
  • Apply the 10% decay to dollars instead of retention share.
  • Miss the month count and include too many tail terms.
  • Skip a sanity check on the final revenue scale.

Как отвечать на собеседовании

  • Write the first few terms explicitly before using a geometric-series formula.
  • Say the unit out loud: dollars per acquired user over one year.