Inside Day

What this pattern measures

An inside day is a session whose RTH high is below the previous session’s high AND whose RTH low is above the previous session’s low. The session sits entirely inside the prior range — a compression bar.

Definitions used on this page:

• Sessions are aggregated from RTH bars only (08:30 to 15:00 Central Time for CME equity index futures).
• The pattern looks at the next session after the inside day and classifies the outcome:
  • Up follow-through: next session’s close is above the inside day’s high
  • Down follow-through: next session’s close is below the inside day’s low
  • Indecisive: close stayed inside the inside-day range, regardless of intraday excursion

Why it matters

Inside days are widely treated as breakout precursors. The compression supposedly reflects indecision that resolves into a directional move. The numbers below say how often that resolution actually arrives by the next session’s close, and how big the move tends to be.

How to read the numbers

• Follow-through rates are the share of inside days that closed past the prior range on the next session, split by direction.
• Indecisive rate captures inside days that produced no clean resolution. A high indecisive rate suggests the compression often persists rather than resolving immediately.
• Avg up/down excursion measures how far past the inside-day high or low the next session reached, regardless of where it closed. High excursion plus low follow-through points to a “false break” tendency.

What’s not here

• Multi-session resolutions. The window is one session.
• Volume confirmation on the inside day itself.
• Filtering for inside days that follow strong trend bars vs. neutral bars.