Overview

Cluster activities are not associated with content objects; therefore there is no direct way for learner progress information to be applied to a cluster activity. The Instructional Management Systems Simple Sequencing (IMS SS) Specification provides a way to define how learner progress for cluster activities is to be evaluated. A set of zero or more Rollup Rules may be applied to a cluster activity and the rules are evaluated during the Overall Rollup Process.

Each Rollup Rule consists of:

  • a set of child activities to consider
  • a set of conditions evaluated against the tracking information of the included child activities
  • a corresponding action that sets the cluster’s tracking status information if the set of conditions evaluates to True.

Rollup Rules have no effect when defined on a leaf activity.

Default Rules

If Rollup Rules are not defined, the default rules are implemented. There are two pairs of default rules, completed/incomplete and satisfied/not satisfied. These are defined in the Rollup Behavior section of the Sharable Content Object Reference Model (SCORM®) Sequencing and Navigation book.

The rules are:

  1. If all satisfied, Then satisfied
    If all (attempted or not satisfied), Then not satisfied
  2. If all completed, Then completed
    If all (attempted or incomplete), Then incomplete

The defaults are applied in pairs, if either action of the pair (complete/incomplete or satisfied/not satisfied) is defined; neither default of the pair is applied. Defining one action of a pair does not affect the other pair applying in default.

Default Rules Examples

The following are two examples of how default rules function:

Example 1:

If any not satisfied, then not satisfied.

  • No default satisfied rule applied, but default completed/incomplete rules are applied.

Example 2:

If at least 50% of the children attempted, then completed.
If any incomplete, then not satisfied.

  • No default rules at all.

Condition Combinations

For each activity included in rollup, individual conditions can be combined to create a set of conditions such that any one individual condition must be True or all conditions must be True. The result of evaluating the Condition Combination for each activity included in rollup is evaluated against the Rollup Rule’s defined Child Activity Set to determine if the resulting action should be triggered. Rule conditions are combined in evaluating the rule using either All or Any. The table below gives a description of the Condition Combination element.

Rollup Conditions

The Rollup Conditions element contains a set of conditions that are evaluated in the context of each activity included in the evaluation of the Rollup Rule. The Rollup Conditions element consists of one or more individual Rollup Condition elements that are combined as defined by the Condition Combination applied to the Rollup Rule. Each Rollup Condition element must be one member of the set of restricted vocabulary tokens that are based on elements in the Tracking Model.

Rollup Condition Operator

The Rollup Condition Operator element is an optional element that may be applied to each Rollup Condition element. It indicates a unary logical operation to be applied after the evaluation of the Rollup Condition. The table below describes the two unary logical operations supported.

Rollup Child Activity Set

By default, tracking status information for all children of a cluster is considered in the rollup evaluations of the cluster. A Content Developer may explicitly restrict how and when an activity’s tracking status information should be included during rollup evaluations:

  • By defining Tracked to be False – This indicates that the activity does not maintain any tracking status information; therefore the activity is never included during rollup.
  • By defining Rollup Objective Satisfied to be False – This indicates that the activity is not included in the evaluation of Rollup Rules having a Satisfied or Not Satisfied Rollup Action.
  • By defining Rollup Objective Measure Weight to be 0.0 – This indicates that the activity’s measure does not contribute to the average weighted measure of its parent.
  • By defining Rollup Progress Completion to be False – This indicates that the activity is not included in the evaluation of Rollup Rules having a Completed or Incomplete Rollup Action.

Rollup Child Activity Set

The Rollup Conditions are applied to all of the included activities during a rollup rule evaluation. The Rollup Child Activity Set element defines how the results of the included activity’s condition evaluations are used to determine if the Rollup Action applies. The Child Activity Set consists of a fixed vocabulary describing when the Rollup Action should be applied and is described in the table to the right.

Rollup Actions

The Rollup Action element describes the desired action that should be applied to the cluster activity that defines the Rollup Rule. The Rollup Action is applied during the Rollup Behavior if the condition set applies to the activities included in the rollup evaluation as defined by the rule’s Rollup Child Activity Set. The Rollup Action may affect the tracking status model for the activity the Rollup Rule is associated with, as defined in the table to the right.

Conclusion

The ability to track learner progress throughout a learning experience is key for Content Developers and Instructional Designers. Without Rollup Rules, tracking specific aspects of learner progress is limited and therefore based on the default rollup rules.

For more information on the Overall Rollup Process, please refer to the SCORM documentation at the ADLNet.gov Web site (www.adlnet.gov).