ARIMA models are essential in Time Series forecasting.
You can add multiple components to make them fit your particular data:
go from a basic AR model to a complex SARIMAX model! 🧵 👇
🔴 S (Seasonal):
• Represents recurring patterns or variations at fixed intervals in time series data.
• When to consider: when there are predictable, repetitive cycles, such as monthly or yearly patterns.
🟢 AR (Auto-Regressive):
• Reflects the relationship between the current observation and its past values at lag intervals.
• When to consider: when there's a correlation between the current and past observations, indicating temporal dependence.
🟡 I (Integrated):
• Represents the number of differences needed to make a time series stationary.
• When to consider: to achieve stationarity, especially in the presence of trends or seasonality.
🔵 MA (Moving Average):
• Describes the relationship between the current observation and residual errors from a moving average model applied to lagged observations.
• When to consider: when there is evidence of residual correlations after differencing.
🟣 X (eXogenous):
• Represents additional variables external to the time series that can influence it.
• When to consider: when there are external factors impacting the time series but not inherently part of it.
⚠️ But be careful!
Don't use components that you don't need or you may overfit your data!
If you liked this you must definitely check yesterday's thread 👇
ARIMA is really useful for time series forecasting, however you can only forecast 1 variable at a time...
VAR (Vector AutoRegression) solves this problem!
Discover more 🧵 👇
▶️ VAR handles multiple interdependent time series.
It's like a network where each series is forecasted based on its own history and the history of others, revealing the interconnected nature of variables.
▶️ ARIMA is tailored for individual series, adept at capturing and predicting patterns when data shows trends or seasonality.
It's the go-to model for detailed single-variable forecasting.
Smoothing data in a time series refers to the process of removing short-term fluctuations or noise from the data in order to reveal underlying trends, patterns, or long-term variations.
There are several reasons why you may need to smooth your data in a time series 👇👇👇
1️⃣ Noise reduction:
Time series data often contain random variations or noise that can make it difficult to discern the underlying patterns or trends.
👉Smoothing techniques help reduce this noise, making it easier to identify meaningful patterns and relationships.
Do you know that you can separate trend and seasonality in your time series data?
Two popular decomposition methods are Seasonal Decompose and STL (Seasonal-Trend decomposition using LOESS).
Let's find out more about them 🧵👇
1️⃣ Seasonal Decompose is a straightforward method that splits a time series into trend, seasonality, and noise. It uses Moving Averages to do so.
Best for datasets with clear and consistent seasonal patterns. It assumes that the seasonal component repeats identically over time.
However, Seasonal Decompose has its limitations... It often struggles with edge data points due to its reliance on moving averages, which can result in missing information at the beginning and end of the series.
Also, it is not capable to extract changing seasonality and trends.