RTH open vs midday mistake-rate split

[Fairman]

On **RTH open vs midday mistake-rate split**, the desk standard stays practical. Splitting mistake rates between RTH open and midday stops a common lie: averaging a disciplined open with a leaky midday into "I'm fine this week."

A journal that does not change next week's size, skip, or sticky line is theater. Tags beat unexplained equity curves.

## Rails that stay on the sheet
- Split to see truth.
- Aggregates hide.
- Invalidation written in cents or an auditable structure break before entry.

## Framework I will not skip
1. Write the definition before the open (level, trigger, invalidation in cents, size, max loss). Verbal plans do not count.
2. Liquidity and spread gates beat narrative. If live spread exceeds max, observe or cut — the chart can still "look perfect."
3. One clean attempt per idea in a window. Failed attempt means new structure, not revenge.
4. Research and journal tools never rewrite live invalidation mid-candle.
5. Tag the trade or the skip the same day — Sunday-you cannot fix what Monday-you did not name.

## Worked example — Aggregated mistake rate hides open
Overall mistakes look OK; open mistake rate awful. Split RTH open vs midday mistake rates; fix the worse bucket first.

I keep examples in cents and clock time so Sunday review can tag the behavior — not rewrite it as a mood.

## Failure modes
- Ignoring the rails above on **RTH open vs midday mistake-rate split** and substituting confidence.
- Adding size after adverse selection because the story still feels right.
- Paying open microstructure tax that midday memory never modeled.

## When to skip
Skipping is a first-class decision — even when the chart still looks persuasive:
- Checklist incomplete at 09:20 ET — observe or one pre-written A+ only.
- Live spread outside max for that symbol and session bucket.
- Index violently disagrees with a single-name thesis and no reduced-size RS plan is on the sheet.
- Platform, hotkeys, locate, or flatten path unverified after reconnect/update.
- Daily loss, PDT slot, or prop buffer tripwire already touched.
- News/FOMC/CPI window where the size-cut card says stand down.

## Closing
For **RTH open vs midday mistake-rate split**, keep operable boredom: written rails, measured cents, index context when relevant, and a skip that needs no apology. Process quality beats ticket volume.