estimate-calibrator

Produce calibrated three-point effort estimates with PERT aggregation and uncertainty analysis.

310|45|Updated Feb 22, 2026
One-click install
npx skills add https://github.com/Mathews-Tom/praxis-skills --skill estimate-calibrator
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: estimate-calibrator
Source: https://github.com/Mathews-Tom/praxis-skills/tree/main/skills/estimate-calibrator
Command: npx skills add https://github.com/Mathews-Tom/praxis-skills --skill estimate-calibrator

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Teams and stakeholders often rely on single-point guesses that hide uncertainty and lead to missed deadlines and mistrust. This Skill replaces one-number estimates with structured three-point (best/likely/worst) estimates, documented assumptions, identified unknowns, and PERT-based aggregation so decisions reflect realistic risk and confidence.

Core Features & Use Cases

  • Decompose and estimate: Break work into atomic tasks (1 hour–3 days preferred) and capture best, likely, and worst durations per task.
  • Uncertainty identification: Categorize unknowns (technical, scope, external, integration, organizational) and document impact and mitigations.
  • Statistical aggregation: Compute PERT expected values, per-task standard deviations, and aggregate uncertainty via root-sum-square to produce confidence intervals.
  • Calibration & recommendations: Apply historical calibration ratios, suggest buffers by confidence level, and recommend spikes for dominant unknowns.
  • Use Case: Estimate adding OAuth2 to an API, migrating a monolith to microservices, or sizing a feature where stakeholders require transparent ranges and confidence rationale.

Quick Start

Provide a short work description and task list to receive best/likely/worst times per task, PERT expected totals, identified unknowns with categories, and a confidence rationale.

Frequently Asked Questions about estimate-calibrator

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I calculate PERT expected values for three-point effort estimates?

To calculate PERT expected values for three-point effort estimates, you provide best, likely, and worst durations per task to compute expected totals, per-task standard deviations, and aggregate uncertainty via root-sum-square for confidence intervals.

What is the best way to estimate software features with unknowns and uncertainty?

The best way to estimate software features with unknowns is using calibrated three-point estimates that identify technical, scope, and external unknowns, document mitigations, and recommend buffers or spikes based on assigned confidence levels.

How do I aggregate uncertainty across multiple project tasks?

You aggregate uncertainty across multiple project tasks by computing PERT expected values and per-task standard deviations, then applying root-sum-square aggregation to produce overall project confidence intervals and transparent sizing ranges.

When do I need three-point estimates instead of single-point guesses for infrastructure changes?

You need three-point estimates for infrastructure changes when single-point guesses hide uncertainty and risk causing missed deadlines, requiring structured best, likely, and worst durations with documented assumptions for stakeholder transparency.

Can I use PERT estimation for migrating a monolith to microservices?

Yes, you can use PERT estimation for migrating a monolith to microservices by decomposing the work into atomic tasks, capturing three-point durations, identifying integration unknowns, and calculating confidence rationale for stakeholders.

Why does my project estimation miss deadlines even with task sizing?

Project estimation misses deadlines because single-point guesses lack uncertainty ranges, whereas applying PERT aggregation with root-sum-square and historical calibration ratios surfaces realistic risk, identifies dominant unknowns, and recommends appropriate buffers.