A Step-by-Step Analytical Framework
This framework outlines a systematic approach to building your forecast model within a spreadsheet application (e.g., Microsoft Excel, Google Sheets).
1. Consolidate and Clean Historical Data
Begin by aggregating data from the past 12-24 months into a single master sheet. Essential data points include:
- Order History:
- QC Data:
- Seasonal Events:
Clean the data by removing duplicates, standardizing formats, and correcting obvious errors to ensure analysis accuracy.
2. Analyze Sales Trends and Seasonality
Create pivot tables and charts to visualize demand patterns.
- Calculate average monthly sales
- Identify growth trends
- Pinpoint clear seasonal spikes
3. Integrate QC Insights for Net Required Stock
QC data is critical for adjusting gross demand figures. Calculate a "QC Adjustment Factor"
Example Formula:Net Required Units = Forecasted Demand / (1 - Average Defect Rate)
If you forecast a demand of 1,000 units and the historical defect rate for that supplier is 5%, you would plan to procure approximately 1,053 units to meet the net demand.
4. Calculate Key Forecasting Metrics
Establish key metrics in your spreadsheet to guide purchasing decisions:
- Lead Time Demand:
- Safety Stock:Safety Stock = (Max Daily Sales * Max Lead Time) - (Average Daily Sales * Average Lead Time).
- Reorder Point (ROP):ROP = Lead Time Demand + Safety Stock.
5. Build a Dynamic Forecast Model
Synthesize the above steps into a unified forecast dashboard. Your model should allow you to:
- Input a future period (e.g., next quarter).
- Automatically pull in historical averages and apply trend multipliers.
- Adjust for planned marketing events.
- Output a recommended purchase quantity per SKU, already adjusted for expected QC losses.
Conclusion
By systematically analyzing previous orders and QC data within spreadsheets, ACBUY users can build a robust, iterative model for inventory forecasting. This analytical approach transforms raw data into strategic intelligence, enabling accurate stock allocation that minimizes costs, maximizes service levels, and supports sustainable business growth. Start with historical data, apply these analytical steps, and refine your model continuously for increasingly precise forecasts.