Forecast Issues
This guide helps resolve problems with demand forecasting.
Common Forecast Problems
Forecasts Showing Zero
Cause 1: No sales history
Products without sales cannot be forecasted.
Solution:
- Wait until product has sales
- Forecasts will generate as data accumulates
Cause 2: New product
Recently added products lack historical data.
Solution:
- Allow 14+ days of sales data
- Monitor product manually until forecasts develop
Cause 3: Inventory tracking not enabled
Products must have inventory tracking for forecasting.
Solution:
- Enable inventory tracking in Shopify
- Wait for sync
- Forecasts will generate as sales occur
Forecasts Seem Inaccurate
Cause 1: Insufficient history
| Data Amount | Accuracy Level |
|---|---|
| < 14 days | Limited |
| 14-30 days | Basic |
| 30-90 days | Good |
| 90+ days | Best |
Solution:
- Wait for more data to accumulate
- Use higher safety stock in the meantime
Cause 2: Unusual events
Promotions, viral moments, or stockouts skew data.
Solution:
- Allow time for forecasts to normalize
- Adjust safety stock temporarily
Cause 3: Seasonal products
Seasonal patterns need full cycle data.
Solution:
- First season forecasts will be limited
- Accuracy improves after full cycle
Cause 4: Wrong threshold settings
Incorrect lead time or safety stock affects recommendations.
Solution:
- Review settings
- Compare to actual supplier times
- Adjust as needed
Daily Consumption Seems Wrong
Cause 1: Recent changes
Sales velocity can change quickly.
Solution:
- Recent data weighted more heavily
- Wait for patterns to stabilize
Cause 2: Stockout periods
If product was out of stock, sales were artificially zero.
Solution:
- Understand context
- Forecasts will adjust as normal sales resume
Cause 3: Calculation period
Consumption is averaged over historical period.
Solution:
- Check what period is being used
- Consider if it's representative
Reorder Recommendations Wrong
Cause 1: Lead time setting
Incorrect lead time causes timing issues.
Solution:
- Verify actual supplier lead time
- Update Lead Time in settings
- Include all delivery steps
Cause 2: Safety stock setting
Too low = stockout risk Too high = overstock risk
Solution:
- Review safety stock days
- Adjust based on experience
Cause 3: Consumption rate changes
If sales velocity changed, recommendations may lag.
Solution:
- Wait for forecasts to adapt
- Manually adjust if urgent
Improving Forecast Quality
Ensure Data Quality
- Accurate Shopify inventory
- Completed orders properly recorded
- Consistent order processing
Provide Adequate History
- More data = better forecasts
- 30+ days recommended
- Full season for seasonal items
Set Realistic Thresholds
- Use actual lead times
- Appropriate safety stock
- Review settings periodically
Monitor and Adjust
- Compare forecast vs actual
- Adjust settings based on results
- Be patient with new products
Understanding Forecast Limitations
Forecasts are based on historical patterns. They don't account for:
- Planned promotions
- Marketing campaigns
- Competitor actions
- Supply disruptions
- Economic changes
Consider these factors when making final decisions.
When Forecasts Won't Help
Some situations are difficult to forecast:
- Brand new products (no history)
- One-time/unique items
- Highly irregular demand
- Products with few sales
For these, rely on:
- Manual judgment
- Higher safety stock
- Frequent monitoring
Getting Help
If forecast issues persist:
- Review this guide
- Check Forecast Accuracy concepts
- Contact support
Include:
- Specific products affected
- What seems wrong
- Your expectations vs reality
Related: Understanding Forecast Accuracy | Common Issues