Estimation

Estimation

Estimate the work for "$ARGUMENTS". Select an estimation method, establish reference stories for calibration, estimate each story relative to references, flag stories needing splitting, and calculate total backlog size and sprint projections.

Prerequisites

Check that .project/$ARGUMENTS/00-initiate.md exists. If it does not, tell the user to run an Initiate skill first (e.g., project-charter) and stop.

If the user passes --skip-checks, skip the prerequisite check and log the skip to .project/$ARGUMENTS/skip-log.md with a timestamp and reason.

Process

1. Read existing context:

   • Read .project/$ARGUMENTS/00-initiate.md for charter and team context
   • Read .project/$ARGUMENTS/01-plan.md if it exists (for backlog, user stories, and roadmap)
   • Read plugins/project-management/shared/scrum-guide.md for Scrum alignment

2. Select the estimation method:

   • Story points with Fibonacci scale (recommended): 1, 2, 3, 5, 8, 13, 21 — measures relative complexity, effort, and uncertainty
   • T-shirt sizing: XS, S, M, L, XL — useful for early rough estimation before detailed planning
   • Planning poker: team-based estimation using story points with discussion rounds
   • Document the selected method and rationale
   • If the team has an existing preference, use that

3. Establish reference stories (calibration):

   • Select 2-3 well-understood stories from the backlog as reference points:
     • "1" story — the simplest meaningful change (e.g., update a label, add a tooltip)
     • "5" story — moderate complexity (e.g., build a form with validation, add a new API endpoint)
     • "8" story — significant complexity (e.g., implement a multi-step workflow, add a new integration)
   • Document why each reference story was chosen and what makes it that size
   • These references anchor all subsequent estimates

4. Estimate each story relative to references:

   • Compare each story to the reference stories: is it simpler, similar, or more complex?
   • Assign a story point value from the Fibonacci scale
   • Consider three dimensions: complexity (how hard?), effort (how much work?), uncertainty (how unknown?)
   • Document brief rationale for estimates that may be surprising (very high or very low)
   • For T-shirt sizing: map XS=1, S=2, M=3-5, L=8, XL=13+

5. Flag stories that need splitting:

   • Any story estimated at >13 points should be flagged for splitting
   • Stories at 13 points should be reviewed — can they be split for lower risk?
   • For flagged stories, suggest splitting strategies (by workflow, data variation, operation, or persona)
   • Re-estimate the split stories

6. Calculate total backlog size:

   • Sum all story points across the entire backlog
   • Break down by epic, theme, priority (Must/Should/Could), and release milestone
   • Calculate MVP size (total points for Must-have or Release 1 stories)
   • Identify the largest epics and any estimation outliers

7. Estimate sprint and timeline projections:

   • For new teams: assume velocity of 20-30 points per sprint (start conservative at 20)
   • For existing teams: use average of last 3 sprints as velocity baseline
   • Calculate: number of sprints = total backlog size / expected velocity
   • Project timeline: number of sprints x sprint length
   • Calculate MVP delivery estimate separately
   • Add buffer: +20% for known risks, +40% for high-uncertainty projects
   • Compare projected timeline with roadmap milestones — flag misalignments

8. Write the artifact — append to .project/$ARGUMENTS/01-plan.md under a ## Estimation section:

   • Method — selected estimation approach and rationale
   • Reference Stories — calibration stories with point values and rationale
   • Estimated Backlog — each story with its estimate, organized by epic
   • Stories to Split — flagged stories with recommended splitting strategies
   • Backlog Size Summary — total points, breakdown by epic/priority/release
   • Sprint Projections — velocity assumption, number of sprints, projected timeline, buffer

Output

Estimation appended to .project/$ARGUMENTS/01-plan.md. Present a summary highlighting:

• Estimation method used and reference stories selected
• Total backlog size in story points
• MVP size and estimated delivery timeline
• Number of stories flagged for splitting
• Projected number of sprints with buffer