Figure 3.

Template for computing the median values of an attribute (for each patient). The SQL code inserts sorted Patient_ID and attribute values into a table, TempMed1, that automatically creates sequentially numbered records (with the sequence number the RecID field). The maximum and minimum RecIDs for each patient are then determined, and the “middle” RecIDs computed. For patients with an odd number of values, there is a single “middle” value, while for patients with an even number of values, there are two “middle” values. The values corresponding to these RecIDs are then extracted into another table, TempMed2, and the median for each patient is determined by taking the average of the two values (for even numbers) or using the single value (for odd numbers).