Glossary

Every term used in a memo, in plain language — and exactly how it's computed from public App Store data.

Demand: How big the audience for this niche is.; Log-scaled total review count across all apps matching the niche (Apple hides install counts, so reviews are the proxy). ~1k ratings ≈ 0, ~10M ≈ 100.
Reachability (free ASO): Can you get discovered on App Store search without paying for installs?; Demand weighted by how beatable the field is. High demand + weak/stale incumbents = high reachability. High demand + strong incumbents = LOW (you'd have to buy installs). This is the #1 survival factor.
Supply weakness: How beatable the current apps are.; Inverse of incumbent strength: driven by average rating of the top apps, how many are well-rated with real volume, and what share haven't updated recently.
Payability: Is there proof people will actually pay?; Highest when paid-upfront apps already have real traction (willingness-to-pay demonstrated). Lowest when the field is entirely free-to-install (revenue would depend on in-app purchases / subscriptions).
Stale leader: A top app that has stopped shipping updates.; A top-10 app whose latest version was released more than 180 days ago. A high stale share means an active developer can out-ship the incumbents.
Strong competitor: A genuinely established, well-liked app.; 500+ ratings AND a 4.3★+ average. Counting these gauges how crowded the 'good apps' tier is.
Free to install: Share of apps with no upfront price.; Note the blind spot: 'free' means no upfront cost, NOT no revenue — most free apps monetize via in-app purchases / subscriptions, which the public API doesn't expose.
Stickiness: Retention potential — does the niche make a daily habit or a one-and-done tool?; A proxy inferred from the app category mix (Health/Productivity/Social rank high; Utilities/Reference low), weighted by ratings. NOT measured retention — a directional hint. It's what decides whether revenue recurs or churns.
Composite · Prize · Winnability: How the factors combine into a portfolio view.; Prize (worth winning?) = demand × payability × stickiness × momentum. Winnability (can you win?) = reachability × supply weakness. Composite = all six, as a weighted GEOMETRIC mean so a single fatal factor tanks it. You set the weights on the Portfolio map — it compares, it doesn't recommend.
Momentum / velocity: How fast an app is gaining ratings or moving in rank.; Computed from the difference between two stored snapshots over time (History tab). Needs at least two captures — Apple only exposes 'today,' so this is accumulated locally.
Band & rank: How a 0–100 score compares to the other niches scanned.; Band = Low (<35) / Moderate / Strong / Very strong (70+). Rank shows where the niche sits among all scanned niches (1 = best), with the peer median for reference.