This function calculates the mean of a selection of the values of an attribute in a case. The selection is a “window” of samples for that attribute, beginning some number of days ago, and including some number of numerical values. The current sample is never used in calculating the result, whatever the number of values required for the baseline.
For example, suppose we have a case with values for the attribute Creatinine:
20 Dec 12 20 Jan 13 20 Feb 13 20 Mar 13 20 Apr 13 14 May 13 Creatinine 50 60 70 80 90 100
We can define a CVA named “Baseline” with the following formula:
baseline mean of first 3 Creatinine values beginning 90 days ago
Then the evaluation for this case will be:
20 Dec 12 20 Jan 13 20 Feb 13 20 Mar 13 20 Apr 13 14 May 13 Creatinine 50 60 70 80 90 100 Baseline 80.0