Time Series Analysis & Decomposition
Time Series Analysis and Decomposition is a systematic approach to studying sequential data collected over successive time intervals. It involves analyzing the data to understand its underlying patterns, trends, and seasonal variations, as well as decomposing the time series into its fundamental components. This decomposition typically includes identifying and isolating elements such as trend, seasonality, and residual (error) components within the data.
Different Time Series Analysis & Decomposition Techniques
- Autocorrelation Analysis: A statistical method to measure the correlation between a time series and a lagged version of itself at different time lags. It helps identify patterns and dependencies within the time series data.
- Partial Autocorrelation Functions (PACF): PACF measures the correlation between a time series and its lagged values, controlling for intermediate lags, aiding in identifying direct relationships between variables.
- Trend Analysis: The process of identifying and analyzing the long-term movement or directionality of a time series. Trends can be linear, exponential, or nonlinear and are crucial for understanding underlying patterns and making forecasts.
- Seasonality Analysis: Seasonality refers to periodic fluctuations or patterns that occur in a time series at fixed intervals, such as daily, weekly, or yearly. Seasonality analysis involves identifying and quantifying these recurring patterns to understand their impact on the data.
- Decomposition: Decomposition separates a time series into its constituent components, typically trend, seasonality, and residual (error). This technique helps isolate and analyze each component individually, making it easier to understand and model the underlying patterns.
- Spectrum Analysis: Spectrum analysis involves examining the frequency domain representation of a time series to identify dominant frequencies or periodicities. It helps detect cyclic patterns and understand the underlying periodic behavior of the data.
- Seasonal and Trend decomposition using Loess: STL decomposes a time series into three components: seasonal, trend, and residual. This decomposition enables modeling and forecasting each component separately, simplifying the forecasting process.
- Rolling Correlation: Rolling correlation calculates the correlation coefficient between two time series over a rolling window of observations, capturing changes in the relationship between variables over time.
- Cross-correlation Analysis: Cross-correlation analysis measures the similarity between two time series by computing their correlation at different time lags. It is used to identify relationships and dependencies between different variables or time series.
- Box-Jenkins Method: Box-Jenkins Method is a systematic approach for analyzing and modeling time series data. It involves identifying the appropriate autoregressive integrated moving average (ARIMA) model parameters, estimating the model, diagnosing its adequacy through residual analysis, and selecting the best-fitting model.
- Granger Causality Analysis: Granger causality analysis determines whether one time series can predict future values of another time series. It helps infer causal relationships between variables in time series data, providing insights into the direction of influence.
Time Series Analysis & Decomposition Techniques: Python and R Implementations
Time Series Analysis Techniques |
Python implementations |
R implementations |
---|---|---|
Autocorrelation Analysis |
||
Partial Autocorrelation Functions (PACF) |
||
Trend Analysis |
Read here |
|
Seasonality Analysis |
Read here |
|
Decomposition |
Read here |
|
Spectrum Analysis |
Read here |
Read here |
Seasonal and Trend decomposition using Loess (STL) |
Read here |
|
Rolling correlation |
||
Cross-correlation Analysis |
Read here |
|
Box-Jenkins Method |
Read here |
|
Granger Causality Analysis |
Read here |
Read here |
Time Series Analysis and Forecasting
Time series analysis and forecasting are crucial for predicting future trends, behaviors, and behaviours based on historical data. It helps businesses make informed decisions, optimize resources, and mitigate risks by anticipating market demand, sales fluctuations, stock prices, and more. Additionally, it aids in planning, budgeting, and strategizing across various domains such as finance, economics, healthcare, climate science, and resource management, driving efficiency and competitiveness.