Another important component of a system is the relationship among the objects. These relationships are usually identified by the links among objects in a system. This linkage reflects the transfer of something, such as data or signals, from one object to another. For example, one object produces an output that is used by another object or another system. A typical scenario on a project is that a deliverable produced in one phase is input to another in a subsequent phase.
A key concept about linkage of objects is the distinction between independence and interdependence. Independence is the degree of autonomy an object has from other objects within a system while pursuing its goals. Interdependence is the degree of interaction among objects to achieve a common goal. Both independence and interdependence are "two sides of the same coin," meaning that both exist to varying degrees vis- -vis one another.
Integration reflects the relative degrees of independence and interdependence in the relationship. It is the combination of independence and interdependence that influences how effectively and efficiently a system achieves its goals. An example in project management is the extent to how much autonomy, e.g., independence, a team member has vis- -vis how much he must work with others, e.g., interdependence, to achieve a common goal efficiently and effectively, e.g., integration.
Relationships can be categorized differently. One category is explicit and implicit. An explicit relationship is obvious, such as a person who provides specific data to another to produce a deliverable. An implicit relationship is not often discernible, such as informal approval of a politically powerful stakeholder. Often, the informal network serves as a perfect example of an implicit relationship.
Another category is symmetrical and asymmetrical relationships. A symmetrical relationship reflects a balance among all the objects or functions within a system, e.g., cost, schedule, and quality. An asymmetrical relationship reflects an imbalance, such as an overemphasis on cost at the expense of schedule and quality.
Relationships can be causative or correlative. A causative relationship is when the action and output of one object causes the behavior of another object. The former is referred to as being independent and the latter dependent. An example is a task that cannot begin until the predecessors have finished.
A correlative relationship exists when an object does something that influences a change in behavior of another object. There does not appear to be a direct relationship between the former and the latter due to some intervening object affecting the relationship. An example is reducing a budget to pressure the same outcome in the scope of a deliverable.
Relationships can be hierarchical, relational, or integral. A hierarchical relationship is when certain objects, such as people or functions, have a more important or decisive role in a system. An example is a project manager who insists on requiring his or her own approval for taking action.
A relational relationship exists when the objects are relatively equal to one another, almost in a neural network format. An example is a project manager who exercises a fairly democratic approach to decision making.
An integral relationship involves both hierarchical and relational aspects. An example is a project manager who employs participative decision making by consulting with team members , but exercises ultimate decision-making authority.