You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 6 Next »

The following are general recommended steps to support implementation of Trial Design datasets to represent the design of a trial. 


to move from more-familiar concepts, such as arms, to less-familiar concepts, such as elements and epochs. In practice, the actual process to represent a trial may depart from these numbered steps. Some steps will overlap; there may be several iterations; and not all steps are relevant for all studies.

  1. Start from the flow chart or schema diagram usually included in the trial protocol. This diagram will show how many arms the trial has, and the branch points or decision points where the arms diverge.
  2. Write down the decision rule for each branching point in the diagram. Does the assignment of a subject to an arm depend on a randomization? On whether the subject responded to a trial assessment? On some other criterion?
  3. If the trial has multiple branching points, check whether all the branches that have been identified really lead to different arms. The arms will relate to the major comparisons the trial is designed to address. For some trials, there may be a group of somewhat different paths through the trial that are all considered to belong to a single arm.
  4. For each arm, identify the major time periods of evaluations of the tobacco product, a subject assigned to that arm will go through. These are the elements, or building blocks, of which the arm is composed.
  5. Define the starting point of each element. Define the rule for how long the element should last. Determine whether the element is of fixed duration.
  6. Re-examine the sequences of elements that make up the various arms and consider alternative element definitions. Would it be better to “split” some elements into smaller pieces or “lump” some elements into larger pieces? Such decisions will depend on the aims of the trial and plans for analysis.
  7. Compare the various arms. In most clinical trials, especially blinded trials, the pattern of elements will be similar for all arms, and it will make sense to define trial epochs. Assign names to these epochs. During the conduct of a blinded trial, it will not be known which arm a subject has been assigned to, or which treatment elements they are experiencing, but the epochs they are passing through will be known.
  8. Identify the visits planned for the trial. Define the planned start timings for each visit, expressed relative to the ordered sequences of elements that make up the arms. Define the rules for when each visit should end.
  9. Identify the inclusion and exclusion criteria to be able to populate the Trial Inclusion/Exclusion Criteria (TI) dataset. If inclusion and exclusion criteria were amended so that subjects entered under different versions, populate TIVERS to represent the different versions.
  10. Populate the TS dataset with summary information.

  • No labels