T-Shirt Sizing Rubric

Every ticket is sized by three roles (PM, PO, Dev) using a t-shirt scale, sealed-bid. Avi (PO) is accountable for the official size; PM and Dev sizes are calibration signals that reveal systematic bias.

The scale

Size	Effort	Scope	Examples (this codebase)
S	< 2 hours	One file, one concept	Reorder agents, swap a thumbnail, copy tweak
M	½ day to 1 day	One feature, one surface	Add a filter, new ERB view, simple migration
L	2–4 days	Multi-surface, one feature	Feature touching backend + UI + migration
XL	1+ weeks	Cross-cutting, multi-feature	Org redesign, new app, cross-app refactor

Hard rule: XL tickets MUST be broken up before build begins. An XL is a planning failure — kick back to refinement. Any Dev assigned an XL may reject it for break-up.

Sealed-bid workflow

1. Ticket opened with problem/goal
2. Alex submits pm_size      (gut from business value)
3. Avi refines spec + acceptance criteria
4. Avi submits po_size       (informed by spec, blind to Alex's)
5. Avi assigns to a Dev
6. Dev submits dev_size      (informed by spec, blind to both)
7. All three revealed simultaneously, locked
8. Build → QA → Release
9. actual_size set post-release (Steffon or Avi)

Visibility: until all three sizes are submitted, each role sees only their own. After all three submit, every role sees every size — forever. Locked at submit; no edits.

This is what makes the bids sealed. Anchoring kills the signal.

What "official" size means

po_size (Avi's number) is the planning of record. Sprint commitments, throughput math, and Avi's accuracy KPI all run off po_size.

pm_size and dev_size are calibration data — they reveal who sees what:
- PM consistently lighter → business-value optimism (typical PM bias)
- Dev consistently heavier on certain task types → discomfort or unfamiliarity worth flagging
- All three diverging → spec ambiguity worth refining harder before locking

Accuracy

Per-role accuracy = average absolute distance between your size and actual_size across all completed tickets, computed on the ordinal scale (S=1, M=2, L=3, XL=4).

Tracked per role, visible on each agent's show page.

• Avi's accuracy is his primary measurable KPI.
• PM and Dev accuracy are visible but not gating — feedback for self-calibration.

When actual_size is set

After release, by Steffon or Avi:
- Look at cycle time, total churn, and scope at ship
- Pick the size that best describes what shipped, not what was planned

If a ticket scope-crept mid-flight (Avi added AC after Dev sized it), record a scope_creep event separately — don't punish the dev_size estimator for moving goalposts.