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Duration Estimation

Completion requirements
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Introduction

It involves assessing the number of work periods needed to complete each identified activity.

Activity duration estimating represents the act of quantifying the amount of time that it is anticipated for the activity to be completed.

CPM Definitions

Early Start:  The earliest date by which an activity can start.

Early Finish:  The earliest date by which an activity can be completed.

Late Start:  The latest date by which an activity needs to start before it will delay the project’s completion date.

Late Finish:  The latest date by which an activity needs to be completed so that it will not delay the project’s completion date.

Target Start:  The date an activity is planned to start.

Target Finish: The date activity is planned to finish.

Process

Responsible functional managers must evaluate each activity and must submit their best estimates based on historical data.

Functional managers must submit their estimates using three possible completion assumptions:

  • Most optimistic completion time (a): This time assumes that everything will go according to plan
  • Most pessimistic completion of time (b): This time assumes that everything will not go according to plan and that the maximum potential difficulties will develop.
  • Most likely completion time (m): This is the time that will most often occur.

The activity duration can be found from the expression:

Activity Duration (te) = a + 4m + b

                                             6

te = activity duration

a = most optimistic time

b = most pessimistic time

m = most likely time

Task:  Calculate the activity duration from the following info:

Most optimistic time = 6 days

Most pessimistic time = 17 days

Most likely time = 10 days

Answer………………………