The Detrend analysis removes trends from time series by either subtracting or dividing, depending on the chosen method. This is useful when you want to concentrate on the cyclical component of a series.
The cyclical component is one of four components of a time series. It refers to (regular or periodic) fluctuations around the trend, excluding the irregular component, revealing a succession of phases of expansion and contraction.
Here, you can define which statistical measure should be used as the trend that will be removed. The available measures are:
- Linear trend
- Exponential trend
This is the calculation that will be used to remove the trend. For the linear and exponential trend methods, you can select between subtract (the statistical measure will be subtracted from the time series) and multiply (the series will be divided by the statistical measure). For the other methods, subtract is the chosen operation.
From & To
You can set a date range for removing a trend.
In this example, we subtracted the linear trend from the US real GDP (expressed in log).
Here, we used median as the trend to subtract from the series.
How to find a trend with Detrend analysis?
Detrend finds cyclical component of time series. To see a trend use Statistics analysis with 'Method: Trend' before adding Detrend.