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:

  1. Enable inventory tracking in Shopify
  2. Wait for sync
  3. Forecasts will generate as sales occur

Forecasts Seem Inaccurate

Cause 1: Insufficient history

Data AmountAccuracy Level
< 14 daysLimited
14-30 daysBasic
30-90 daysGood
90+ daysBest

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:

  1. Review settings
  2. Compare to actual supplier times
  3. 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:

  1. Verify actual supplier lead time
  2. Update Lead Time in settings
  3. 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:

  1. Review this guide
  2. Check Forecast Accuracy concepts
  3. Contact support

Include:

  • Specific products affected
  • What seems wrong
  • Your expectations vs reality

Related: Understanding Forecast Accuracy | Common Issues