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3.12. Randomization Controls
Randomization Controls, Table 3.12a, describe when and what actions the LMS will take to reorder the available children of encountered cluster activities, while performing the various sequencing behaviors (refer to Section 4: Sequencing Behavior). Content developers may apply Randomization Controls to any cluster in the activity tree.
Table 3.12a: Description of Randomization Controls
No. | Name | Description | Value Space | Default Value |
1 | Randomization Timing | Indicates when the ordering of the children of the activity should occur. Never – Randomization is never applied. Once – Randomization is applied before the first attempt on the activity. On Each New Attempt – Randomization is applied before each new attempt on the activity. | Vocabulary | Never |
2 | Randomize Children | Indicates that the order of the child activities is randomized (True or False). | boolean | False |
Source: IMS Simple Sequencing Behavior and Information Model [1]
The two Randomization Controls elements are tightly coupled. First, The Randomization Timing element indicates when, if ever, the children of a cluster should be reordered. The Randomization Timing element is a vocabulary with the following values:
Never (default value): Randomization shall never be applied to cluster.
Once: Randomization shall be applied before the first attempt on the cluster.
On Each New Attempt: Randomization shall be applied before each new attempt on the cluster.
The normative Sequencing Behavior Pseudo Code (refer to Appendix C) does not explicitly state when the Randomize Children Process is invoked. The LMS is responsible for ensuring the application of the Randomize Children Process is consistent with the defined value of the Randomization Timing element, as described in Section 4.7: Selection and Randomization Behavior.
Second, the Randomize Children element indicates whether the children of the cluster should be reordered. This element contains a boolean (True/False) value. The default value for Randomize Children, if not defined explicitly for the activity, is False.
ADL Note: For any reordering of a cluster’s children to occur, regardless of the value of the Randomization Timing element, the Randomize Children element must explicitly be defined as True.
The Randomization Controls elements have no effect when defined on a leaf activity.