Trial Elements (TE)

The Trial Elements domain contains the element code that is unique for each element, the element description, and the rules for starting and ending an element.

The TE dataset contains the definitions of the elements that appear in the Trial Arms (TA) dataset. An element may appear multiple times in the TA table because it appears either (1) in multiple arms, (2) multiple times within an arm, or (3) both. However, an element will appear only once in the TE table.

Each row in the TE dataset may be thought of as representing a "unique element" in the same sense of "unique" as a CRF template page for a collecting certain type of data is referred to as "unique page." For instance, a CRF might be described as containing 87 pages, but only 23 unique pages. By analogy, the trial design matrix in TA Example Trial 1 (See Trial Arms (TA) has 12 study cells, each of which contains 1 element, but the same trial design matrix contains only 6 unique elements, so the TE dataset for that trial has only 6 records.

An element TOBA-731 - Getting issue details... STATUS is a building block for creating study cells, and an arm is composed of study cells. Or, from another point of view, an arm is composed of elements; that is, the trial design assigns subjects to arms, which comprise a sequence of steps (elements). The element typically indicates the study product being administered ( e.g., Study Product A)  or, if no study product is being administered , the other activities that are the purpose of this period of time (e.g., "Screening", "Follow-up", "Washout"). In some cases, this time period may be quite passive (e.g., "Rest"; "Wait, for protocol defined event").

Trial elements represent an interval of time that serves a purpose in the trial and are associated with certain activities affecting the subject. “Week 2 to week 4” is not a valid element. A valid element has a name that describes the purpose of the element and includes a description of the activity or event that marks the subject's transition into the element as well as the conditions for leaving the element.

The trial in Section 3.3.1.1.2, Trial Arms (TA) Example 1 is assumed to have fixed-duration elements. The wording in TESTRL is intended to separate the description of the event that starts the element into the part that would be visible to a blinded participant in the trial (e.g., "First dose of a product epoch") from the part that is revealed when the study is unblinded (e.g., "where dose is 5 mg"). Care must be taken in choosing such descriptions to ensure that they are arm- and epoch-neutral. For instance, in a crossover trial such as Trial Arms Example 2, where an element may appear in 1 of multiple epochs, the wording must be appropriate for all possible epochs (e.g., "OPEN LABEL PRODUCT"). The CDISC Submission Data Standards Team is considering adding a separate variable to the TE dataset that would hold information on the product that is associated with an element. This would make it clearer which elements are "product elements” and, therefore, which epochs contain product elements and thus are "product epochs."