Glossary
Short definitions of product analytics terms, grouped by topic; the count is the number of terms in the section.
Statistics 4
Bootstrap The bootstrap estimates a statistic's distribution by resampling with replacement, without relying on asymptotic formulas or normality. Minimum detectable effect (MDE) The MDE is the smallest effect a test can reliably detect given its sample size, significance level, and power. p-value A p-value is the probability of seeing an effect at least as large as observed when the null hypothesis is true. It is not the chance the effect is random. Statistical power Statistical power is the probability of detecting an effect of a given size when it truly exists. It equals one minus the Type II error rate.
Experiments 4
A/A test An A/A test serves the same experience to both groups and validates the tooling — split, metrics, and standard error — before the main experiment. CUPED CUPED cuts metric variance with a pre-experiment covariate, delivering the same effect estimate at a smaller standard error and higher power. Sample Ratio Mismatch (SRM) SRM is a gap between the observed and expected split. On a large sample it signals broken randomisation, not random noise. Uplift modelling Uplift modelling predicts the causal effect of a treatment on an individual user rather than their outcome — which is what separates it from a plain forecast.
Product 8
Churn Churn is the share of users who stop being active over a period. It is the flip side of retention and a direct input to LTV. Cohort A cohort is a group of users sharing a common start time or event. It is the foundation of cohort-based retention analysis. DAU / MAU and stickiness DAU and MAU are the unique active users per day and per month; their ratio, stickiness, shows how far the product became a habit. Funnel A funnel is a sequence of steps from entry to a target action with conversion between them. It shows where users are lost. North Star metric A North Star metric reflects the value the product delivers to users and predicts long-term business growth. Retention Retention is the share of users who return to the product after their first interaction. It is a core measure of value and stickiness. Retention curve A retention curve plots the share of returning users by period after start. Its shape is the signature of the product and its stability. Time to convert Time to convert is the delay from entry to a target action. It shows how fast a cohort converts, not just its final share.
Data 2
Business 3
ARPU ARPU is the average revenue per user over a period. A basic input to LTV and unit economics, sensitive to the mix of the active base. LTV LTV is the total value of a user over their entire lifetime. It is the key benchmark for acquisition and retention economics. NPS NPS is a loyalty index from a single 0–10 question: the share of promoters minus the share of detractors, sensitive to how responses are collected.