A dependency defines a sequential relationship between dimensions, constraints and resources. Dependencies are explicitly set or can be inferred when other dependencies exist at broader levels in the work item dimension hierarchy. Dependencies form the logical path of execution when calculating the start and finish dates of all work items and constraints.
Sequence Dependency -Defines a successor relationship between two or more dimensions or work items. The work item cannot start without the completion of one or more preceding work items constrained by the dependency whether applied to the work item directly or to one of its dimensions. Dependencies can have the traditional relationship constraints of Critical Path Method (CPM) but the use of leads and lags would indicate work items not scoped to the correct level of granularity and as such are discouraged.
Dependencies between work items represent a physical constraint where one item cannot be installed until the prior items is complete. Analysis of these dependencies would show the quickest possible construction duration absent of any other constraint.
Dependencies between dimensions represent the desired sequencing of work items. This is done for the purposes of resource leveling, varying occupancy requirements or other environmental considerations. They are also implicitly inherited down the dimension hierarchy so a dependency defined at a higher level value is enforced for all work items that are scoped to any child value.
Constraint Dependency - Constraints can have dependencies defined between two or more constraint classes that imply a priority or a sequential relationship between them. For example and RFI normally proceeds an ASI. A constraint dependency could be defined between the RFI constraint class and the ASI constraint class and when both are linked to a dimension or work item the critical path calculation would infer the RFI workflow must be complete prior to the ASI workflow starting. Dependencies could be defined at any or all of the scope levels.
Resource Dependency – CEM would provide the framework for designating who within the general contractor’s team has responsibility over what portions of the work. When a resource is assigned to the project, their scope of responsibility is determined by linking the assignment to one or more dimensions in the CEM model. The hierarchical nature of dimensions allows for assignments to be made at varying levels in the tree structure forming a chain of responsibility for every work item and constraint. On small projects the resource assignment would be made at a high level dimension with no other assignments lower in the dimension tree. Thus direct responsibility for all work items falls under that single resource. On larger projects, senior management would be assigned at a high level in the dimension hierarchy with additional resources assigned lower in the tree. This distributes responsibility within the project team but maintains the responsibility chain for oversight and issue escalation. This also ensures that all work items have at least one primary point of contact.
By assigning resources to dimensions – the overall duration of the assignment, workload and potential resource over/under utilization could be derived from the model. The model would require that all assignments are unique across dimensions. This ensures each work item has a single primary point of contact with zero to multiple supervisory points of contact higher in the dimension hierarchy.
Using this concept, complex workflow routing could be achieved with very little administrative effort. For example, if an assistant project manager is assigned to the Work Result::Concrete for Constructed Entity::Building 2, he would be responsible to prepare and manage the execution of the subcontract agreement for this work. The work flow rules for this constraint class require supervisory approval if the value is greater than $50,000. The workflow engine would know the reporting relationship based on the dimension hierarchy and route the approval accordingly.
All activities required to manage a constraint or work item would be the responsibility of the primary point of contact. All communication scoped to the appropriate dimensions would be routable to the correct team members based on primary and or supervisory point of contact. All progress reporting and other management responsibilities would done by the primary point of contact and would be held responsible by the supervisory points of contact.