Solution Quality Metrics
Understanding solution quality goes beyond simple feasibility. This guide explains the key metrics for evaluating VRP solutions, how to interpret them, and strategies for improvement.What Makes a Good Solution?
A high-quality VRP solution balances multiple objectives:Core Quality Metrics
1. Feasibility Rate
The percentage of jobs successfully assigned:2. Occupancy
How full the schedule is in terms of work time versus available time:Work Time includes:
- Travel time
- Service time
- Wait time (if any)
- Shift duration minus breaks
- < 60%: Underutilized - consider reducing fleet
- 60-85%: Optimal range - good efficiency with buffer
- > 85%: High utilization - limited flexibility
- > 95%: Over-stretched - risk of delays
3. Workload Fairness
Measures how evenly work is distributed across resources:4. Travel Efficiency
Multiple metrics evaluate routing efficiency:Total Distance & Time
Distance per Job
Circuity Factor
5. Time-Based Metrics
On-Time Performance
Wait Time Analysis
High wait times indicate:
- Poor time window alignment
- Suboptimal route sequencing
- Need for dynamic scheduling
Advanced Quality Indicators
Service Level Metrics
Cost Effectiveness
Comparing Solutions
When evaluating alternative solutions:Multi-Criteria Comparison
Pareto Optimization
Often no single “best” solution exists. Consider Pareto-optimal solutions:A solution is Pareto-optimal if improving one metric necessarily worsens another. Keep multiple Pareto-optimal solutions for different scenarios.
Weighted Scoring
Create a composite score based on business priorities:Improvement Strategies
For Low Feasibility
1
Enable Partial Planning
2
Relax Constraints
Convert hard constraints to soft where possible
3
Add Resources
Increase fleet size or extend shifts
4
Review Requirements
Check if all constraints are necessary
For Poor Efficiency
For Imbalanced Workload
Monitoring Quality Over Time
Track metrics to identify trends:Quality Benchmarks
Industry standards for different sectors:Sector | Feasibility | Occupancy | On-Time | Fairness |
---|---|---|---|---|
Parcel Delivery | 98%+ | 75-85% | 95%+ | 0.80+ |
Field Service | 95%+ | 65-75% | 90%+ | 0.85+ |
Food Delivery | 99%+ | 70-80% | 98%+ | 0.75+ |
Medical Transport | 100% | 60-70% | 99%+ | 0.90+ |
Benchmarks vary by region, business model, and service level agreements. Use these as starting points and adjust based on your specific requirements.
Best Practices
Quality Management Guidelines:
- Define Success Metrics: Establish clear KPIs before optimization
- Regular Monitoring: Track metrics daily/weekly
- Iterative Improvement: Make small, measured changes
- Balance Trade-offs: No solution is perfect in all dimensions
- Document Decisions: Record why certain trade-offs were made
- Benchmark Regularly: Compare against historical performance