I build satultra , a digital SAT practice site. After a practice test, most tools lead with one number, and a 1290 says how you did, not what to study next.

The digital SAT is built around 29 skills: College Board's question bank lists 10 in Reading and Writing and 19 in Math. If every answer is filed under one of them, the results page can show where the points went. Here's how that works in a React and Firestore app: one taxonomy file, an append-only event log, pure reducers and a planner.

One taxonomy file, one canonical id

Over several imports, the same skill showed up as "Central Ideas and Details", "central ideas & details" or just 1 .…