About Derivation Procedures

Derivation Procedures perform calculations on collected data to derive related values; for example, convert values to alternate units (such as pounds to kilos), or compute a value from other data (such as patient age from birth date and visit date). You specify the Question Groups, Questions and clinical planned events (CPEs; usually visits) to use as input and write a calculation that results in the response to a derived Question.

You must create a derived Question to receive the derived value. You define derived Questions in the Global Library the same way as other Questions, except that you must select their Derived? box. You then add them to a Question Group in a study DCM. Alternatively, you can mark a Question as derived in a study DCM Question Group, even if it is not defined as derived in the Global Library. You can also choose whether or not to display the derived Question in the Data Entry window (though it cannot be enterable).

You can include validation tests in a Derivation Procedure to test data before you perform calculations on it. Oracle Clinical reports any discrepancies it finds to the Discrepancy Database. See "Using the Discrepancy Database" in Oracle Clinical Conducting a Study.

Note:

You can test data values before derivation in the same procedure, but to test the derived value you must create a separate procedure.

You can specify the order in which Derivation Procedures are executed during batch validation in the same study, so that you can use the derived value in other Derivation Procedures.

For more information, see:

• Restrictions on Derivation Procedures
  
• Examples of Derivation Procedures
  

Restrictions on Derivation Procedures

The following restrictions apply to Derivation Procedures:

• Each derived Question is derived by one and only one Derivation Procedure, and each Derivation Procedure calculation detail derives one and only one derived Question. It is possible to have multiple calculation details in a single procedure, each one deriving a value for a different derived Question.

• You must denote the Question Group that contains the derived Question as the primary reference Question Group.

  Note:

  The cursor for the primary reference Question Group is the outermost Procedure Question Group Cursor (see How Procedures Work Internally). The response values to the primary Question Group are therefore fetched before any other responses in the Procedure, and the derived value is derived once for each instance of that outermost Procedure Question Group Cursor, with the final value derived at the end of the Procedure (only the final derived value is stored). In other words, if the derivation involves multiple Question Groups/cursors, the value of the derived response can change until all of the inner cursors are through looping for a given derived outer cursor.

  Since validation tests are performed in the innermost loop, use caution when testing the derived value in such procedures. You may prefer to use a separate validation procedure to validate derived values.

• You cannot create a DCM based entirely on derived Questions or populate a DCM entirely with derived data.

• You must create the derived Question before you create the Procedure that will derive its response (see Questions and Question Groups).

Examples of Derivation Procedures

Following are two examples of simple Derivation Procedure calculation expressions.

Temperature Unit Conversion Given a temperature measured in centigrade, calculate the equivalent Fahrenheit value:

(9/5*TEMPERATURE_C)+32

Weight Unit Conversion Given a weight measured in pounds, calculate the equivalent metric (kg) value:

A.WEIGHT_LBS/2.21