Improving Retail Forecast Accuracy with Machine Learning

The global retail market continues to grow larger and the influx of consumer data increases daily. The rise in volume, variety, and velocity of data poses challenges with demand forecasting and inventory planning. Outdated systems generate inaccurate demand forecasts. This results in multiple challenges for retailers. They are faced with over-stocking and lost sales, and often have to rely on increased levels of safety stock to avoid losing sales.

A recent McKinsey study indicates that AI-based forecasting improves forecasting accuracy by 10–20 percent. This translates to revenue increases of 2–3 percent. An accurate forecasting system can also help determine ideal inventory levels and better predict the impact of sales promotions. It provides a single view of demand across all channels and a better customer experience overall.

In this blog post, we will show you how to build a reliable retail forecasting system. We will use Amazon Forecast, and an AWS-vetted solution called Improving Forecast Accuracy with Machine Learning. This is an AWS Solutions Implementation that automatically produces forecasts and generates visualization dashboards. This solution can be extended to use cases across a variety of industries.

Improving Forecast Accuracy solution architecture

This post will illustrate a retail environment that has an SAP S/4 HANA system for overall enterprise resource planning (ERP). We will show a forecasting solution based on Amazon Forecast to predict demand across product categories. The environment also has a unified platform for customer experience provided by SAP Customer Activity Repository (CAR). Replenishment processes are driven by SAP Forecasting and Replenishment (F&R), and SAP Fiori apps are used to manage forecasts.

The solution is divided into four parts: Data extraction and preparation, Forecasting and monitoring, Data visualization, and Forecast import and utilization in SAP.

Figure 1. Notional architecture for improving forecasting accuracy solution and SAP integration

­­Data extraction and preparation

Historical demand data such as sales, web traffic, inventory numbers, and resource demand are extracted from SAP and uploaded to Amazon Simple Storage Service (S3). There are multiple ways to extract data from an SAP system into AWS. As part of this architecture, we will use operational data provisioning (ODP) extraction. ODP acts as a data source for OData services, enabling REST-based integrations with external applications. The ODP-Based Data Extraction via OData document details this approach. The steps involved are:

1. Create a data source using transaction RSO2, allow Change Data Capture for specific data to be extracted
2. Create an OData service using transaction SEGW
3. Create a Data model for ODP extraction, which refers to the defined data source, then register the service
4. Initiate the service from SAP gateway client
5. In the AWS Management Console, create an AWS Lambda function to extract data and upload to S3. Check out the sample extractor code using Python, referenced in the blog Building data lakes with SAP on AWS

Related data that can potentially affect demand levels can be uploaded to Amazon S3. These could include seasonal events, promotions, and item price. Additional item metadata, such as product descriptions, color, brand, size may also be uploaded. Amazon Forecast provides built-in related time series data for holidays and weather. These three components together form the forecast inputs.

Forecasting and monitoring

An S3 event notification will be initiated when new datasets are uploaded to the input bucket. This in turn, starts an AWS Step Functions state machine. The state machine combines a series of AWS Lambda functions that build, train, and deploy machine learning models in Amazon Forecast. All AWS Step Functions logs are sent to Amazon CloudWatch. Administrators will be notified with the results of the AWS Step Functions through Amazon Simple Notification Service (SNS).

An AWS Glue job combines raw forecast input data, metadata, predictor backtest exports, and forecast exports. These all go into an aggregated view of forecasts in an S3 bucket. It is then translated to the format expected by the External Forecast import interface. Amazon Athena can be used to query forecast output in S3 using standard SQL queries.

Data visualization

Amazon QuickSight analyses can be created on a per-forecast basis. This provides users with forecast output visualization across hierarchies and categories of forecasted items. It also displays item-level accuracy metrics. Dashboards can be created from these analyses and shared within the organization. Additionally, data scientists and developers can prepare and process data, and evaluate Forecast outputs using an Amazon SageMaker Notebook Instance.

Forecast import and utilization in SAP

Amazon Forecast outputs located in Amazon S3 will be imported into the Unified Demand Forecast (UDF) module within the SAP Customer Activity Repository (CAR). You can read here about how to import external forecasts. An AWS Lambda function will be initiated when aggregated forecasts are uploaded to the S3 bucket. The Lambda function performs a remote function call (RFC) to the SAP system through the official SAP JCo Library. The SAP RFC credentials and connection information may be stored securely inside AWS Secrets Manager and read on demand to establish connectivity.

Once imported, forecast values from the solution can be retrieved by SAP Forecasting and Replenishment (F&R). They will be consumed as an input to replenishment processes, which consist of requirements calculation and­­­­­ requirement quantity optimization. SAP F&R calculates requirements based on the forecast, the current stock, and the open purchase orders. The requirement quantity then may be improved in accordance with optimization settings defined in SAP F&R.

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Additionally, you have the flexibly to adjust the system forecast as required by the demand situation or analyze forecasts via respective SAP Fiori Apps.

Sample use case: AnyCompany Stores, Inc.

To illustrate how beneficial this solution can be for retail organizations, let’s consider AnyCompany Stores, Inc. This is a hypothetical customer and leader in the retailer industry with 985 stores across the United States. They struggle with issues stemming from their existing forecasting implementation. That implementation only understands certain categories and does not factor in the entire product portfolio. Additionally, it is limited to available demand history and does not consider related information that may affect forecasts. AnyCompany Stores is looking to improve their demand forecasting system.

Using Improving Forecast Accuracy with Machine Learning, AnyCompany Stores can easily generate AI-based forecasts at appropriate quantiles to address sensitivities associated with respective product categories. This mitigates inconsistent inventory buys, overstocks, out-of-stocks, and margin erosion. The solution also considers all relevant related data in addition to the historical demand data. This ensures that generated forecasts are accurate for each product category.

The generated forecasts may be used to complement existing forecasting and replenishment processes. With an improved forecasting solution, AnyCompany Stores will be able to meet demand, while holding less inventory and improving customer experience. This also helps ensure that potential demand spikes are accurately captured, so staples will always be in stock. Additionally, the company will not overstock expensive items with short shelf lives that are likely to spoil.

Conclusion

In this post, we explored how to implement an accurate retail forecasting solution using a ready-to-deploy AWS Solution. We use generated forecasts to drive inventory replenishment optimization and improve customer experience. The solution can be extended to inventory, workforce, capacity, and financial planning.

We showcase one of the ways in which Improving Forecast Accuracy with Machine Learning may be extended for a use case in the retail industry. If your organization would like to improve business outcomes with the power of forecasting, explore customizing this solution to fit your unique needs.

Further reading:

• From forecasting demand to ordering – An automated machine learning approach with Amazon Forecast to decrease stockouts, excess inventory, and costs
• Technical Guide: Time Series Forecasting Principles with Amazon Forecast
• Big Data Analytics – Forecasting