Moving Average

This column outputs a centered moving average.

Centered averages calculate the average for a value in a column by averaging that value, along with a number of values in the column prior to and preceding that value. For example, if a report outputs the number of incidents per month, a centered average for March that uses three data points would use the number of incidents from February, March, and April to derive the average.

Tip: Moving averages work best using odd numbers of data points, but can use an even number, though the internal calculation to derive the value will differ somewhat.

For an odd number of data points, the centered average at i for a given data point, di, and number of data points, N, is:

(di-(N-1)/2 + di-(N-1)/2 +1 + ...di + ...di + (N-1)/2 -1 + di + (N-1)/2)/N.

For an even number of data points, the centered average at i for a given data point, di, and number of data points, N, is:

(di-N/2 + 2*di-N/2 +1 + ...2*di + ...2*di + N/2 -1 + di + N/2)/2N.

When you add a report moving average column to a report, the calculation automatically uses three data points. However, the number of data points can be changed. See Change the Number of Data Points.