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3.11. Selection Controls
Content developers have the ability to define sequencing information that indicates when to select certain activities and limit the number of activities to be chosen. This enables a rule that can be written to state to an LMS’s sequencing implementation, e.g., “pick 4 of the 6 activities on the first attempt of an activity.” Table 3.11a describes the Selection Controls.
Table 3.11a: Description of Selection Controls
No. | Name | Description | Value Space | Default Value |
1 | Selection Timing | Indicates when selection should occur. Never – Selection is never applied; all of the children of the activity are selected by default. Once – Selection is applied before the first attempt on an activity. On Each New Attempt – Selection is applied before each new attempt on an activity. The On Each New Attempt option and its associated behavior are not specified in this version of SCORM. | Vocabulary | Never |
2 | Selection Count Status | Indicates the Selection Count data (True or False) is meaningful for the activity. | boolean | False |
3 | Selection Count | Indicates the number of child activities that must be selected from the set of child activities associated with the activity. If Selection Count is larger than the number of child activities, all child activities are selected. This value is unreliable unless Selection Count Status is True. If Selection Count Status is False, all child activities are selected. | Non Negative Integer | 0 |
Source: IMS Simple Sequencing Behavior and Information Model [1]
The three Selection Controls elements are tightly coupled. First, the Selection Timing element indicates when, if ever, the children of a cluster should be selected. The Selection Timing element is a vocabulary with the following values:
Never (default value): Selection shall never be applied to cluster. All of the cluster’s children, as defined in the activity tree, are available by default.
Once: Selection shall be applied before the first attempt on the cluster.
On Each New Attempt: Selection 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 Select Children Process is invoked. The LMS is responsible for ensuring the application of the Select Children Process is consistent with the defined value of the Selection Timing element, as described in Section 4.7: Selection and Randomization Behavior.
Second, the Selection Count element indicates how many of the cluster’s children should be selected. This element contains a non-negative integer value. The default value for Selection Count, if not defined explicitly for the activity, is 0. If the Selection Count exceeds the cluster’s number of children, then all of the children will be selected.
Third, the Selection Count Status element indicates whether the value of Selection Count is valid. This element contains a boolean (True/False) value. The default value for Selection Count Status, if not defined explicitly for the activity, is False.
ADL Note: For selection of a cluster’s children to occur, regardless of the value of the Selection Timing element, the Selection Count Status element must be explicitly defined to be True and Selection Count must explicitly be defined to be some non-zero integer. Otherwise, all of the cluster’s children, as defined in the activity tree, are available by default.
The Selection Controls elements have no effect when defined on a leaf activity.