Intermediate everything in Growth & Experimentation, page 8
The Peak-End Rule: Design for Memory, Not Averages
Users don't remember the average of an experience; they remember its most intense moment and its end. This shapes recall of onboarding, support calls, or checkout. The footgun is optimizing for overall 'goodness' while ignoring a painful peak or weak ending.
Anchoring Bias: The First Number You See Matters Most
The first number you see acts like a mental anchor, warping all subsequent judgments. This is used in pricing, where a high "original" price makes a sale price seem better, and in negotiations.
The Hook Model: Designing for Repeat Engagement
The Hook Model engineers user habits with a 4-step loop: Trigger, Action, Variable Reward, and Investment. It's a framework for building products people return to on their own, common in social media and games.
Fogg Behavior Model: Why Users Act (or Don't)
The Fogg Behavior Model states a behavior only happens when Motivation, Ability, and a Prompt converge (B=MAP). Use it to diagnose why a feature fails or to design new ones. The footgun is blaming low motivation when the real issue is low ability.
The Data Layer: A Central Hub for Website Events
A data layer is a central JavaScript object acting as a message bus between your site and analytics tags. It passes event data, like button clicks or purchase values, in a structured way. The key footgun: never overwrite it; always use dataLayer.push().
Churn Rate: How Fast Your Business is Leaking
Churn rate is your business's leak rate—the percentage of customers lost over a period. It's a vital health metric for subscription services like SaaS or streaming. The footgun?
User Activation: Engineering the 'Aha' Moment
User activation engineers the 'aha' moment when a new user first experiences your product's value. It's measured by a key action, like sending a message in Slack, that predicts retention.
ICE Score: A Quick Framework for Prioritizing Ideas
The ICE score is a quick framework for ranking ideas by asking: what's the potential Impact, our Confidence in the outcome, and the Ease of implementation? Growth teams use it to prioritize experiments, balancing big bets with quick wins.
High-Tempo Testing: Move Faster Than Your Channels Decay
High-tempo testing treats growth as a continuous experiment, not a one-time campaign. Since marketing channels decay quickly, this lets you find new wins across the entire user journey.
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