Mistake trend is a per-tag rolling-window comparison: how often does each mistake-tag appear in the last 30 days vs the preceding 60 days? Two directions:
- Drift — current monthly rate is materially HIGHER than the 60-day baseline. Discipline is decaying.
- Improvement — current monthly rate is materially LOWER than baseline. The rule is sticking.
Rates are normalised to per-month equivalents so the windows can have different lengths without distorting the read. Eligibility: a tag needs ≥ 3 baseline occurrences (else it's too rare to claim a trend) and a drift verdict additionally needs ≥ 3 recent occurrences (improvement doesn't — zero recent is the strongest possible improvement signal).
Across the analysis window: 'no stop' baseline 4 occurrences (rate 2.0/month), recent 8 occurrences (rate 8.0/month) → change +300%. 'panic exit' baseline 6 (rate 3.0/month), recent 1 (rate 1.0/month) → change -67%.
The two directions:
- Drift. Re-read the journal rule that USED to suppress this mistake. Either it stopped being honoured or the trigger has shifted to a new context the rule doesn't cover. Tighten the rule, not the count.
- Improvement. Don't relax. Rules compound only as long as you keep policing them. The improvement signals tell you which rules ARE working — those are the ones to NOT change.
Both directions surface in the same card because both are actionable in different ways. Drift = problem to attack. Improvement = working pattern to protect.
Why monthly-rate equivalents. A trader with 50 trades in the last 30 days and 80 in the preceding 60 days isn't doubling down on discipline if the mistake count is 6 vs 8 — they're trading more, so the relative frequency is what matters. Normalising to per-month equivalents catches this.
Tier: Pro. Wave 6 (Mistake Analysis), pairs with TRA-235 (Top expensive — what's costing you most), TRA-237 (Pair co-occurrence — which mistakes cluster), and TRA-238 (Streak + recovery — sustained discipline).
How to read the card: Hero shows the most-shifted tag with its percent change. Table breaks down the rest with direction labels. Re-look monthly — the rolling windows make weekly inspection too noisy.
Tier: Pro.