Estimate Project Duration n Experience n Historical Data n Research n Modeling n Experiments n Breakdown/Roll-Up n Delphi Method n Consultants n Three Outside Estimates n Ranging

Critical Path This path will determine the length of the project It is considered ‘critical’ for several reasons: n It has no slack n Each activity must start immediately when its predecessor is finished, and consume no more than its allotted time. n Delay of any critical path activity will delay the completion of the entire project.

Duration Estimating n Why is duration estimating so important? n How do I get my team members to stick to the estimated durations n What about when no one will commit to a duration? n How does duration estimating affect project cost? n What are the tricks to estimating durations? n When duration estimates seem out of line, how do I get them adjusted? n We already have a deadline to meet. Why have duration estimate?

Commitment n Estimated during is the estimated time needed to finish a project. n Part of sticking to any estimated duration is having commitment from your project team members. n Inspire commitment in your team by consulting them about the duration. n Consult with your most experienced team member on duration estimating.

Duration versus Effort n Effort: the time one spends performing an activity. n Duration: Includes effort, but also the time spent on other things in between sessions of effort.

Duration Estimating Techniques n Avoid doing estimating yourself, especially if the work happens to fall with your areas of expertise. n Make preliminary planning yourself, and hand over to team members to refine.

Duration Estimating Techniques n Some techniques that might help your team members to perform estimation: –Experience –Historical data –Research –Modeling –Experiments

Duration Estimating Techniques n Continued from previous slide: –Breakdown/Roll-up –Delphi Method –Consultants –Three Outside Estimates –Ranging –Other Techniques –Special Cases

Normal Duration n Determine the most cost-efficient technical approach. n Make an estimate of how long the most cost-efficient method will take to complete. n Selectively adjust your estimate for any activity that is subject to common problems.

CPM versus PERT n PERT: Program Evaluation and Review Technique n CPM: Critical Path Method n PERT uses optimistic, pessimistic and most likely durations (p. 186) n CPM makes only one time estimate for an activity

Calculating Project Duration n Do NOT add all the durations, unless all activities are in series. n Activities on critical path determines the duration of the project n Each activity must start immediately after its predecessor is finished and consume no more than its allocated time. n Delay of any critical path activity will delay the project.

Forward Pass n The approach to determine the duration of the whole project n EPS – Earliest Possible Start time n EPF – Earliest Possible Finish time n DUR – Duration, the elapsed time an activity is expected to finish. n EPF = EPS + DUR

Optimizing the Plan n The need to meet external deadlines. n The first line of defense: Relieve the critical path n The second line of defense: Sharpen your pencil. (Refine Critical Path) n The third line of defense: Crashing Activities (Spend more money in order to shrink the durations of some activities of the project)