4.5.1 Measurements

The basic purpose of measurements in a project is to provide data to project management about the project’s current state, such that they can effectively monitor and control the project and ensure that the project goals are met. As project goals are established in terms of software to be delivered, cost, schedule, and quality, for monitoring the state of a project, size, effort, schedule, and defects are the basic measurements that are needed [43, 75]. Schedule is one of the most important metrics because most projects are driven by schedules and deadlines. Only by monitoring the actual schedule can we properly assess if the project is on time or if there is a delay. It is, however, easy to measure because calendar time is usually used in all plans.

Effort is the main resource consumed in a software project. Consequently, tracking of effort is a key activity during monitoring; it is essential for evaluating whether the project is executing within budget. For effort data some type of timesheet system is needed where each person working on the project enters the amount of time spent on the project. For better monitoring, the effort spent on various tasks should be logged separately. Generally effort is recorded through some on-line system (like the weekly activity report system in [57]), which allows a person to record the amount of time spent against a particular activity in a project. At any point, total effort on an activity can be aggregated.

Because defects have a direct relationship to software quality, tracking of defects is critical for ensuring quality. A large software project may include thousands of defects that are found by different people at different stages. Just to keep track of the defects found and their status, defects must be logged and their closure tracked. If defects found are being logged, monitoring can focus on how many defects have been found so far, what percentage of defects are still open, and other issues. Defect tracking is considered one of the best practices for managing a project [17].

Size is another fundamental metric because it represents progress toward delivering the desired functionality, and many data (for example, delivered defect density) are normalized with respect to size. The size of delivered software can be measured in terms of LOC (which can be determined through the use of regular editors and line counters) or function points. At a more gross level, just the number of modules or number of features might suffice.

For effective monitoring, a project must plan for collecting these measurements. Most often, organizations provide tools and policy support for recording this basic data, which is then available to project managers for tracking.