Investigate what drove a 15% rise in Codecademy sign-ups

You are a product manager at Codecademy, the online platform where people learn to program. Sign-ups are reported to be up 15%. Why might this have happened, and how would you work out which explanation is the right one? ```hint Real, then where Before brainstorming causes, decide how you would know the 15% reflects real new learners rather than a change in how sign-ups are counted. Then think about which ways of slicing the increase would shrink the list of possible causes fastest. ``` ### Clarifying Questions - Does "sign-ups" mean new free accounts, new paid subscriptions, or both? Over what window is the 15% measured, and against which baseline: the previous period or the same period last year? - Did the rise arrive as a sudden step on one date, or build gradually? - Is it concentrated on one platform (web, iOS or Android), in one region, or in one acquisition channel? - Did the team ship or launch anything around that time, such as a change to the sign-up flow, a new course, a marketing campaign or a pricing change? ### What a Strong Answer Covers - Verifying the number first: the definition of a sign-up, the comparison period, seasonality, and tracking or data-pipeline changes. - Segmenting the increase by time, platform, region, channel and user type, and splitting it into more visitors versus a higher sign-up rate. - A structured set of internal and external hypotheses, each paired with the data that would confirm or rule it out, investigated in a sensible order. - Checking quality further down the funnel (new accounts that start a lesson, come back or pay) to tell genuine demand from spam accounts or a gating change. - What to do once the cause is known. ### Follow-up Questions - Sign-ups are up 15% but the number of new learners who start a first lesson is flat. What does that suggest, and what would you check next? - The whole increase comes from a single country where no campaign was running. What could explain it, and how would you confirm it? - How would you tell whether the new accounts are bots or spam?