Compute Running Correlations

Description

Running correlations can be used to detect times when two variables are in and out of phase with one another. This tool computes these correlations based on a window of time specified by the user (see "Window Size" under "Parameters" below). The output consists of correlations, p-values, and the 95% confidence level output to the file specified by the user and displayed under "Output Running Correlations". Clicking the "Plot..." button will display the running the correlations for each year and the 95% confidence intervals, which denote p<0.05.

Input Data

File
Select the input data to analyze by clicking on "Browse" and navigating to the proper file.

Input Data Format
Year / Variable 1 / Variable 2

Each "/" is a tab (i.e., data should be tab-delimited). Missing Data should be denoted as "-99".

Start Row
This input is the row number where the main data to be processed begin in the input file selected above. An example of how row numbers are entered is shown in Figure 2 located in the Running Dendro Tools topic.

Output Data

File
Select or enter the name of the file where the results will be stored.

Header
Information entered here will be output in the first line of the output file.

Parameters

Start Year
Enter the year to start the analysis.

End Year
Enter the year to end the analysis.

Window Size
Enter the size of the window that will be used to compute the running correlations. A "ramp-up" is needed so a start year of 1300 with a window size of 20 will output the first correlation value at 1319. These windows overlap, so a running correlation starting at 1300 will compute the correlation from 1300-1319 (inclusive) and output the corrrelation at the year 1319. Then a correlation from 1301-1320 (inclusive) will be computed and output at the year 1320 and so on.