ARIMA-based Inventory Demand Forecasting: A Practical Time Series Analysis of Retail Transaction Data

This article introduces a project using the ARIMA model for inventory demand forecasting, covering the entire process of data preprocessing, exploratory data analysis, time series prediction, and model evaluation to help retail enterprises optimize inventory management and decision-making. Using historical retail transaction data, the project applies the ARIMA model to identify sales trends and predict future demand, which has significant commercial application value.

In the retail industry, accurate inventory demand forecasting is a key link in optimizing supply chain management, reducing operational costs, and improving customer satisfaction. Excess inventory leads to increased capital occupation and storage costs, while insufficient inventory may result in sales losses and customer churn. This project focuses on using historical retail transaction data for inventory demand forecasting, applying the ARIMA model to help enterprises identify sales trends and predict future demand, covering the entire data science process.

High-quality data is the foundation of model accuracy. Data preprocessing includes handling missing values (filling or deleting), outlier detection and processing, format standardization (unifying date, numerical, and categorical fields), and feature engineering (extracting daily sales volume, transaction frequency, etc.). Exploratory data analysis reveals: seasonal fluctuations and long-term trends in daily sales trends; 7-day moving average to smooth short-term fluctuations and highlight long-term trends; high-value customer analysis to identify the top 10 core customers, facilitating precise marketing and inventory allocation.

The ARIMA model consists of AR (AutoRegressive), I (Integrated), and MA (Moving Average) components: AR uses historical values to capture time dependence, I converts non-stationary sequences to stationary ones, and MA uses historical errors to correct predictions. The parameters (p,d,q) are selected for the optimal combination through ACF/PACF plots and AIC/BIC criteria. The visualization of prediction results compares historical data with predicted values, including historical curves, fitted curves, and future prediction intervals, to intuitively show the model's effect.

Multiple metrics are used to evaluate model performance: Mean Absolute Error (MAE) reflects the average deviation, with smaller values indicating higher accuracy; Root Mean Square Error (RMSE) penalizes large errors more heavily, suitable for scenarios where extreme deviations are to be avoided; Coefficient of Determination (R²) measures the model's ability to explain data variation, with values closer to 1 indicating better fitting effect. Comprehensive metrics fully evaluate model performance and provide support for optimization.

The model has significant application value in retail business: Inventory optimization (determine reasonable inventory levels to avoid capital occupation or sales losses); Supply chain coordination (help suppliers arrange production and optimize logistics distribution); Promotion planning (formulate strategies based on demand trends to maximize sales); Financial budgeting (provide references for fund arrangement and cash flow planning).

The project can be further optimized: Model comparison (compare with Prophet, XGBoost, LSTM); Develop interactive dashboards (dynamically view predictions and adjust parameters); Automate prediction processes (regularly update models and generate reports); Integrate external factors (weather, holidays, promotions, etc., to improve accuracy with multiple variables).

This project demonstrates the practical value of time series analysis in retail inventory management, providing enterprises with an implementable demand forecasting solution. It is an excellent practical case for learners and provides a data-driven decision-making path for practitioners. With the development of AI technology, inventory forecasting will become more accurate, and enterprises should embrace technology and integrate it into operational decisions to maintain a competitive advantage.