Resource Utilization

Factors Influencing the Quality of Estimates

Planning Horizon

Estimates of current events are close to 100 percent accurate but are reduced for more distant events.

Project Duration

Long-duration projects increase the uncertainty in estimates.

People

Accuracy of estimates depends on the skills of the people making the estimates. A close match of people skills to the task will influence productivity and learning time.

Project Structure and Organization

A dedicated project team will have the speed gained from concentrated focus and localized project decisions.

This speed comes at an additional cost of tying up personnel full time. Conversely, projects operating in a matrix environment may reduce costs by more efficiently sharing personnel across projects but may take longer to complete since attention is divided and coordination demands are higher.

Padding Estimates

If everyone at all levels of the project adds a little padding to reduce risk, the project duration and cost are seriously overstated.

Organization Culture

Organizations vary in the importance they attach to estimates.

The prevailing belief in some organizations is that detailed estimating takes too much time and is not worth the effort or that it’s impossible to predict the future.

Other organizations subscribe to the belief that accurate estimates are the bedrock of effective project management. Organization culture shapes every dimension of project management.

Other Factors

Equipment down-time can alter time estimates. National holidays, vacations, and legal limits can influence project estimates. Project priority can influence resource assignment and impact time and cost.

The quality of time and cost estimates can be improved when these variables are considered in making the estimates.

Poor estimates are a major contributor to projects that have failed.

Therefore, every effort should be made to see that initial estimates are as accurate as possible since the choice of...