Forecast Accuracy
Forecast accuracy measures how well your forecasts match actual demand. Understanding and improving accuracy is critical for effective planning.
Recommended Starting Points by Role
Planner (Forecasting + Replenishment)
Start here:
- Accuracy Metrics - Review MAPE, WAPE, and bias metrics
- Forecast vs Actuals - Compare forecasts to actual demand
- Deviation Analysis - Identify products/channels with poor accuracy
- Improvement Actions - Take actions to improve accuracy
Daily workflow:
- Review forecast accuracy metrics
- Compare forecasts to actuals
- Identify accuracy issues
- Adjust forecast models and events
- Track accuracy improvements
Finance (COGS, Holding Cost, Cost-to-Serve)
Start here:
- Accuracy Reports - Generate forecast accuracy reports
- Cost Impact - Analyze forecast accuracy impact on costs
- Bias Analysis - Review forecast bias trends
- Accuracy Trends - Monitor accuracy over time
Daily workflow:
- Review accuracy metrics and trends
- Analyze cost impact of forecast errors
- Monitor bias trends (over/under forecasting)
- Generate accuracy reports for analysis
Executive (Summary Dashboards)
Start here:
- Accuracy Dashboard - High-level accuracy overview
- Accuracy KPIs - Key accuracy performance indicators
- Accuracy Trends - Long-term accuracy trends
Daily workflow:
- Review accuracy dashboard summaries
- Monitor accuracy KPIs
- Track accuracy trends over time
- Review accuracy improvement initiatives
Accuracy Metrics Explained
MAPE (Mean Absolute Percentage Error)
Average percentage error across all forecasts:
MAPE = (1/n) × Σ|Actual - Forecast| / Actual × 100
Interpretation:
- < 10%: Excellent accuracy
- 10-20%: Good accuracy
- 20-30%: Fair accuracy
- > 30%: Poor accuracy (needs improvement)
Use cases:
- Overall forecast accuracy assessment
- Comparing different forecast models
- Tracking accuracy improvements
WAPE (Weighted Absolute Percentage Error)
Weighted average percentage error, giving more weight to high-volume items:
WAPE = Σ|Actual - Forecast| / ΣActual × 100
Interpretation:
- Similar to MAPE but weighted by volume
- Better reflects impact on high-volume items
- More relevant for inventory planning
Use cases:
- Accuracy assessment for high-volume items
- Inventory planning accuracy
- Cost impact analysis
Bias
Measures whether forecasts are consistently over or under:
Bias = (Σ(Forecast - Actual) / ΣActual) × 100
Interpretation:
- Positive Bias: Over-forecasting (forecast > actual)
- Negative Bias: Under-forecasting (forecast < actual)
- Zero Bias: Balanced forecasting (ideal)
Use cases:
- Identifying systematic over/under forecasting
- Adjusting forecast models
- Balancing inventory levels
Hit Rate
Percentage of forecasts within acceptable tolerance:
- Within 10%: Forecasts within 10% of actual
- Within 20%: Forecasts within 20% of actual
- Within 50%: Forecasts within 50% of actual
Use cases:
- Service level assessment
- Planning confidence levels
- Risk assessment
Step-by-Step: Measuring Forecast Accuracy
1. View Accuracy Metrics
- Navigate to Plan → Forecast Accuracy
- Select:
- Forecast Scenario: Scenario to analyze
- Time Period: Date range for analysis
- Products: Products to analyze (or all)
- Channels: Channels to analyze (or all)
- Locations: Locations to analyze (or all)
2. Review Overall Metrics
View overall accuracy:
- MAPE: Mean Absolute Percentage Error
- WAPE: Weighted Absolute Percentage Error
- Bias: Forecast bias
- Hit Rate: Percentage within tolerance
3. Analyze by Dimension
Analyze accuracy by:
- Product: Accuracy per product (identify problem products)
- Channel: Accuracy per channel (identify problem channels)
- Location: Accuracy per location (identify problem locations)
- Time Period: Accuracy over time (identify trends)
4. Review Forecast vs Actuals
- Navigate to Analyze → Forecast vs Actuals
- View side-by-side comparison:
- Forecast values
- Actual values
- Deviation
- Percentage error
5. Identify Problem Areas
Identify:
- Top Under-Forecast: Products/channels consistently under-forecast
- Top Over-Forecast: Products/channels consistently over-forecast
- High MAPE Items: Items with poor accuracy
- Trending Issues: Accuracy getting worse over time
Forecast vs Actuals Analysis
Viewing Forecast vs Actuals
- Navigate to Analyze → Forecast vs Actuals
- Configure:
- Forecast Scenario: Scenario to compare
- Time Period: Date range
- Products: Products to compare
- Channels: Channels to compare
- View comparison:
- Forecast: Forecasted demand
- Actual: Actual demand
- Deviation: Difference (Actual - Forecast)
- Percentage Error: Percentage deviation
Understanding Deviations
Positive Deviation (Actual > Forecast):
- Under-forecasted demand
- Risk of stockout
- May indicate missed events or trends
Negative Deviation (Actual < Forecast):
- Over-forecasted demand
- Risk of overstock
- May indicate events didn’t have expected impact
Deviation Alerts
System can alert when deviations exceed thresholds:
- Alert Threshold: Configurable (e.g., ±20%)
- Alert Frequency: Configurable (e.g., daily, weekly)
- Alert Delivery: Email, webhook, Slack
Note: Push alerts may be work in progress. Check alert configuration for current status.
Improving Forecast Accuracy
1. Apply Events Properly
Action: Ensure all relevant events are applied:
- Promotions
- Seasonality
- Marketing campaigns
- External factors
Impact: Events can significantly improve accuracy when properly applied.
2. Adjust Forecast Models
Action: Try different forecast models:
- Time series models
- Seasonal models
- Trend models
- Custom models
Impact: Different models work better for different products/channels.
3. Review Historical Patterns
Action: Analyze historical demand patterns:
- Identify trends
- Recognize seasonality
- Understand cycles
- Account for anomalies
Impact: Better understanding of patterns improves forecasts.
4. Address Bias
Action: If bias is consistently positive or negative:
- Positive Bias (Over-forecasting): Reduce forecast values
- Negative Bias (Under-forecasting): Increase forecast values
- Adjust forecast model parameters
- Review event applications
Impact: Reducing bias improves overall accuracy.
5. Focus on Problem Areas
Action: Prioritize improving accuracy for:
- High-volume items (biggest impact)
- High-value items (cost impact)
- Problem products/channels (biggest improvement opportunity)
Impact: Focused improvements yield better results.
What Success Looks Like
Planner Success
- ✅ MAPE below 20% for most products
- ✅ Bias near zero (balanced forecasting)
- ✅ Accuracy improving over time
- ✅ Problem areas identified and addressed
- ✅ Forecasts trusted for planning
Finance Success
- ✅ Accuracy metrics tracked regularly
- ✅ Cost impact of forecast errors understood
- ✅ Bias trends monitored
- ✅ Accuracy reports generated for analysis
Executive Success
- ✅ Accuracy meets targets
- ✅ Accuracy trends positive
- ✅ Accuracy improvements demonstrated
- ✅ Forecasts drive confident decisions
Common Pitfalls
1. Not Measuring Accuracy
Problem: Creating forecasts but not measuring how accurate they are.
Solution: Regularly measure forecast accuracy:
- Set up accuracy reviews
- Track accuracy metrics
- Compare forecasts to actuals
- Monitor accuracy trends
How to avoid: Make accuracy measurement part of forecast workflow.
2. Ignoring Bias
Problem: Focusing only on MAPE without addressing bias.
Solution: Monitor and address bias:
- Review bias metrics regularly
- Identify systematic over/under forecasting
- Adjust forecast models to reduce bias
- Track bias trends
How to avoid: Include bias in accuracy reviews.
3. Not Acting on Accuracy Insights
Problem: Measuring accuracy but not taking action to improve.
Solution: Take action based on accuracy insights:
- Identify problem products/channels
- Adjust forecast models
- Apply events properly
- Focus improvement efforts
How to avoid: Make accuracy improvement part of planning process.
4. Not Understanding Channel Policy Effects
Problem: Not understanding how channel policies affect forecast interpretation.
Solution: Understand channel policy effects:
- Review ATP policies
- Understand replenishment rules
- Consider alert thresholds
- Account for channel allocations
How to avoid: Familiarize yourself with channel policy configuration.
Troubleshooting
Accuracy Metrics Not Available
Symptoms: Forecast accuracy metrics not showing or unavailable.
Possible causes:
- Forecasts not generated
- Actuals data not available
- Time period mismatch
- System calculation issue
Steps to resolve:
- Verify forecasts are generated
- Check actuals data availability
- Verify time period alignment
- Review calculation settings
- Contact support if issue persists
Accuracy Consistently Poor
Symptoms: Forecast accuracy (MAPE) consistently high across products/channels.
Possible causes:
- Events not applied
- Forecast models not appropriate
- Insufficient historical data
- External factors not accounted for
- Data quality issues
Steps to resolve:
- Review and apply relevant events
- Try different forecast models
- Verify sufficient historical data
- Account for external factors
- Check data quality
- Adjust forecast parameters
- Monitor accuracy improvements
Bias Not Improving
Symptoms: Forecast bias remains consistently positive or negative.
Possible causes:
- Forecast model parameters not adjusted
- Events not properly applied
- Systematic data issues
- Model not appropriate for data
Steps to resolve:
- Adjust forecast model parameters
- Review event applications
- Check for data quality issues
- Try different forecast models
- Monitor bias trends
Deviation Alerts Not Working
Symptoms: Forecasts deviate significantly but alerts not triggering.
Possible causes:
- Alert thresholds not configured
- Alert policies not enabled
- Deviation calculation issue
- Alert delivery issue
- Push alerts work in progress
Steps to resolve:
- Check alert threshold configuration
- Verify alert policies are enabled
- Review deviation calculations
- Check alert delivery settings
- Verify push alert status (may be WIP)
- Test alert functionality
Related Pages
Permissions & Roles
Viewing forecast accuracy requires standard user permissions. All accuracy metrics are scoped to your organization.