Working with Project Constraints

A constraint is a boundary or limit based on the project. You’ve dealt with constraints before: a preset budget for your project, an inflexible deadline, limited availability of computer hardware, locating a resource with a specific skill. Constraints are any factors that can limit your options. They must be documented, their risks examined, and then the project manager must plan on how to meet the project objectives with the identified constraints.

When it comes to scheduling activities, you can also create constraints on the relationships you assign between your activities. For example, an FS relationship is constrained by the completion of the predecessor before the successor can begin. This is a natural constraint. This relationship between activities is sometimes called hard logic. Hard logic describes the matter-of-fact order of activities. For example, you must install the operating system before you install the application. On the other hand, soft logic is when the project manager decides to do tasks in a particular order based on experience, conditions in the project, time, or other reasons. This logic is also called discretionary logic. For example, it is a good practice to have completed all the coding before beginning the testing phase. It is not mandatory— you can unit test certain modules that are complete before all the coding is done— but it is preferred to have all the coding complete before any testing begins.

Date Constraints

Often in project management, projects have preset deadlines that require project managers to work backward from the assigned completion date. The problem is that the person establishing the deadline may not realize the work required to complete a project by that given date. Unfortunately, this is often the way project management works: you’re assigned a deadline and then you have to figure out how to complete the tasks by that date.

Whenever possible, avoid using specific dates for tasks unless it is absolutely required. The reason that you should avoid date constraints is that you are signifying a certain task must happen on a specific date regardless of the completion of tasks before or after it. The best method of assigning tasks is to use a unit of time and then predict when the task may happen based on the best- and worst-case scenario for the predecessor tasks’ completion. There are three types of date constraints:

No earlier than This constraint specifies that a task may happen any time after a specific date, but not earlier than the given date.

No later than This constraint is deadline orientated. The task must be completed by this date—or else.

On this date This constraint is the most time orientated. There is no margin for adjustment, as the task must be completed on this date, no sooner or later.

These constraints can be set on a task using your project management software.

Management Constraints

Management constraints are dependency relationships imposed because of a decision by management—this includes the project manager. For example, a project manager is overseeing the development of a web-based learning management system. The web site will allow students to register for classes, check grades, and pay for their tuition, all online. The e-commerce portion of the project and the database development portion of the project are scheduled to happen concurrently. Because of the unique relationship between the two tasks, the project manager decides to rearrange the work schedule so the database portion of the project must finish first and then the e-commerce portion of the project may begin. The project manager accomplishes this by changing the relationship between the tasks from start-to-start to finish-to- start. Now the database task must be completed before the development of the e-commerce portion. This is another example of soft logic.

Technical Constraints

Technical constraints stem from FS relationships. Most often within an IT project, tasks will be logically sequential to get from the start to the end. These constraints are the simplest and most likely the ones you’ll find in a project. The technical constraints you may encounter when building your network diagram fall into two major categories:

Discretionary constraints These constraints allow the project manager to change the relationship between activities based on educated guesses. Imagine two tasks that are scheduled to run concurrently. Task A, the design on the web interface, must finish, however, before Task B, the development of the web application, is well under development. Because of the cost associated with the programmer, the project manager changes the relationship between the tasks from SS to FS. Now the first task must finish before the second task begins.

Resource constraints A project manager may elect to schedule two tasks as FS rather than SS based on a limitation of a particular resource. For example, if you are managing a project that requires a C++ programmer for each task and you only have one programmer, then you will not be able to use SS relationships. The sequential tasks that require the programmer’s talents will dictate that the relationship between tasks be FS.

Organizational Constraints

Within your organization there may be multiple projects that are loosely related. The completion of another project may be a key milestone for your own project to continue. Should another project within your organization be lagging, it can impact your own project’s success. For example, a manufacturing company is upgrading its software to track the warehouse inventory. Your project is to develop a web application that allows clients to query for specific parts your company manufactures. The success of your project requires the warehouse inventory project be complete before your project can end. These relationships are entered into your network diagram as FS, with the origin activity representing the foreign project.

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Working with Project Constraints