Differencing is a technique used to make a time series stationary by removing trends or seasonality. It involves subtracting the value of an observation from the previous one. For example, if the original series is [100, 120, 130, 150], the first differenced series becomes [20, 10, 20]. This process is key to applying models like ARIMA that require stationarity. Stationarity means that a time series has a constant mean, variance, and autocorrelation over time. Many real-world datasets, such as sales or temperature data, have trends that need differencing to stabilize them. Without stationarity, model predictions may be inaccurate. Differencing can be applied multiple times, but over-differencing should be avoided as it can introduce noise into the data. Checking plots or performing statistical tests like the Augmented Dickey-Fuller (ADF) test can help confirm whether differencing is sufficient. For instance, a time series that shows a downward trend may need first-order differencing, while seasonal patterns might require seasonal differencing.
What is differencing in time series, and why is it used?

- The Definitive Guide to Building RAG Apps with LlamaIndex
- The Definitive Guide to Building RAG Apps with LangChain
- Accelerated Vector Search
- Large Language Models (LLMs) 101
- Optimizing Your RAG Applications: Strategies and Methods
- All learn series →
Recommended AI Learn Series
VectorDB for GenAI Apps
Zilliz Cloud is a managed vector database perfect for building GenAI applications.
Try Zilliz Cloud for FreeKeep Reading
Are there security risks in vector search systems?
Vector search systems, like any other technological solution, are not immune to security risks. These risks can arise fr
Does Gemini 3 support structured output and function-calling schemas?
Yes, Gemini 3 supports structured output and function-calling schemas as first-class features. In practice, this means y
What are the trade-offs between accuracy and speed in speech recognition?
In speech recognition systems, the trade-off between accuracy and speed is a common challenge faced by developers. Accur