SKILL.md
Project Estimation
Table of Contents
- [Overview](#overview)
- [When to Use](#when-to-use)
- [Quick Start](#quick-start)
- [Reference Guides](#reference-guides)
- [Best Practices](#best-practices)
Overview
Accurate project estimation determines realistic timelines, budgets, and resource allocation. Effective estimation combines historical data, expert judgment, and structured techniques to minimize surprises.
When to Use
- Defining project scope and deliverables
- Creating project budgets and timelines
- Allocating team resources
- Managing stakeholder expectations
- Assessing project feasibility
- Planning for contingencies
- Updating estimates during project execution
Quick Start
Minimal working example:
# Three-point estimation technique for uncertainty
class ThreePointEstimation:
@staticmethod
def calculate_pert_estimate(optimistic, most_likely, pessimistic):
"""
PERT formula: (O + 4M + P) / 6
Weighted toward most likely estimate
"""
pert = (optimistic + 4 * most_likely + pessimistic) / 6
return round(pert, 2)
@staticmethod
def calculate_standard_deviation(optimistic, pessimistic):
"""Standard deviation for risk analysis"""
sigma = (pessimistic - optimistic) / 6
return round(sigma, 2)
@staticmethod
def calculate_confidence_interval(pert_estimate, std_dev, confidence=0.95):
"""
Calculate confidence interval for estimate
95% confidence ≈ ±2 sigma
"""
z_score = 1.96 if confidence == 0.95 else 2.576
// ... (see reference guides for full implementation)Reference Guides
Detailed implementations in the references/ directory:
Guide
Contents
Three-Point Estimation (PERT)
Bottom-Up Estimation
Analogous Estimation
Resource Estimation
Estimation Templates
Best Practices
✅ DO
- Use multiple estimation techniques and compare results
- Include contingency buffers (15-25% for new projects)
- Base estimates on historical data from similar projects
- Break down large efforts into smaller components
- Get input from team members doing the actual work
- Document assumptions and exclusions clearly
- Review and adjust estimates regularly
- Track actual vs. estimated metrics for improvement
- Include non-development tasks (planning, testing, deployment)
- Account for learning curve on unfamiliar technologies
❌ DON'T
- Estimate without clear scope definition
- Use unrealistic best-case scenarios
- Ignore historical project data
- Estimate under pressure to hit arbitrary targets
- Forget to include non-coding activities
- Use estimates as performance metrics for individuals
- Change estimates mid-project without clear reason
- Estimate without team input
- Ignore risks and contingencies
- Use one technique exclusively