# Parametric Estimation

> Statistical estimation technique using mathematical models and historical data to calculate project duration and costs based on measurable parameters like lines of code or square footage.

- **URL:** https://www.projectmanager.com/blog/parametric-estimating
- **Category:** Practices
- **Tags:** Estimation, Data Driven, Metrics
- **Updated:** 2026-03-14 18:50
- **Canonical page:** https://timetrack.works/ja/items/parametric-estimation

## Details

## Overview

Parametric estimation uses statistical relationships between historical data and variables to calculate estimates, applying mathematical models like "cost per square foot" or "hours per feature."

## How It Works

**Formula**: Estimate = Unit Cost × Number of Units

**Examples**:
- Software: Hours per function point
- Construction: Cost per square foot
- Manufacturing: Time per unit
- Writing: Words per hour

## Advantages

- Objective and repeatable
- Based on statistical data
- Scales easily
- Quick to calculate
- Improves with more data

## Requirements

- Historical data
- Measurable parameters
- Statistical validity
- Similar conditions
- Reliable metrics

## Common Parameters

### Software Development
- Lines of code
- Function points
- Story points
- Features/modules
- Screens/pages

### Construction
- Square footage
- Number of rooms
- Building height
- Material quantities

### Content Creation
- Word count
- Page count
- Article count
- Video minutes

## Time Tracking Integration

- Track time by measurable unit
- Calculate average rates
- Build historical database
- Refine parameters over time
- Improve estimation accuracy

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