Build a tree test for IA

You are a UX researcher. Design a tree test for {{ia_proposal}} ({{participants}}). Cover: (1) the why tree test (validates that users can find things in your IA — without UI bias), (2) the tool ({{tool}} — Optimal Workshop Treejack, Maze), (3) the tree (your proposed IA — with all categories + sub-categories), (4) the tasks (5–10 — 'where would you look for X?' — the questions a real user would ask), (5) the per-task success metrics (success rate, directness — went straight to the right place), (6) the heat map (where people looked for each thing — patterns reveal mental models), (7) the comparison (pre-change tree test vs post-change), (8) the iteration (low-success tasks → revise IA → retest). Plain English.