Pairwise Comparison Tool

A web-based tool for making complex decisions using the Analytic Hierarchy Process (AHP) through pairwise comparisons.

Privacy-First Decision Making

• 100% Client-Side: All calculations happen in your browser
• Zero Data Collection: Your decisions stay completely private
• No Account Required: Just open and use
• Local Storage Only: Data saved locally in your browser
• No External Dependencies

About

This tool helps you make better decisions by breaking down complex choices into simple comparisons. It uses the Analytic Hierarchy Process (AHP), a structured method for organizing and analyzing complex decisions.

How It Works

The process happens in 4 steps:

1. Setup: Enter the criteria that matter for your decision (e.g., Price, Quality, Speed)

2. Compare: Make pairwise comparisons between criteria to establish their relative importance

   • Compare two criteria at a time
   • Use a slider to indicate which is more important and by how much
   • The tool will guide you through all necessary comparisons

3. Results: View the weighted importance of each criterion

   • See how your comparisons translate into percentage weights
   • Download the comparison matrix for future use

4. Evaluate: Rate your options against each criterion

   • Enter the options you're considering
   • Rate how well each option performs for each criterion
   • Get a final weighted score that accounts for both criteria importance and option performance

Perfect For

• Product Decisions
• Career Choices
• Feature Prioritization
• Investment Decisions
• Any complex choice with multiple factors

The Math Behind It

1. Pairwise Comparison Matrix: Your comparisons create a matrix where:

   • Each element represents the relative importance of criterion i compared to criterion j
   • If criterion A is 3 times more important than B, then B is 1/3 as important as A
   • The diagonal is always 1 (each criterion compared to itself)

2. Priority Vector: The final weights are calculated by:

   • Normalizing the matrix (dividing each element by its column sum)
   • Taking the average of each row in the normalized matrix

3. Final Scores: Options are scored by:

   • Multiplying each rating by the criterion's weight
   • Summing these weighted ratings for each option

Usage

1. Visit the tool at https://pairwise-compare.vercel.app/
2. Choose between starting a new comparison or uploading an existing matrix
3. Follow the step-by-step process
4. Download your results or continue to evaluate options

Development

The tool is built with vanilla JavaScript and uses modern CSS features. To run locally:

1. Clone the repository
2. Open index.html in a web browser
3. No build process or dependencies required

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.