ch 3: Operations Strategy in a Global Environment Flashcards

Question

Six Steps PERT and CPM

Answer 1

Define the project and prepare the work breakdown structure Develop relationships among the activities – decide which activities must precede and which must follow others Draw the network connecting all of the activities Assign time and/or cost estimates to each activity Compute the longest time path through the network – this is called the critical path . Use the network to help plan, schedule, monitor, and control the projec

Answer 2

When will the entire project be completed? What are the critical activities or tasks in the project? Which are the noncritical activities? What is the probability the project will be completed by a specific date? Is the project on schedule, behind schedule, or ahead of schedule? Is the money spent equal to, less than, or greater than the budget? Are there enough resources available to finish the project on time? If the project must be finished in a shorter time, what is the way to accomplish this at least cost?

Answer 3

The critical path is the longest path through the network The critical path is the shortest time in which the project can be completed Any delay in critical path activities delays the project Critical path activities have no slack time

Answer 4

earliest time at which an activity can start, assuming all predecessors have been completed

Answer 5

earliest time at which an activity can be finished

Answer 6

latest time at which an activity can start so as to not delay the completion time of the entire project

Answer 7

latest time by which an activity has to be finished so as to not delay the completion time of the entire project

Answer 8

If an activity has only a single immediate predecessor, its ES equals the EF of the predecessor If an activity has multiple immediate predecessors, its ES is the maximum of all the EF values of its predecessors ES = Max {EF of all immediate predecessors}

Answer 9

The earliest finish time (EF) of an activity is the sum of its earliest start time (ES) and its activity time EF = ES + Activity time

Answer 10

If an activity is an immediate predecessor for just a single activity, its LF equals the LS of the activity that immediately follows it If an activity is an immediate predecessor to more than one activity, its LF is the minimum of all LS values of all activities that immediately follow it LF = Min {LS of all immediate following activities}

Answer 11

The latest start time (LS) of an activity is the difference of its latest finish time (LF) and its activity time LS = LF − Activity time

Answer 12

Slack is the length of time an activity can be delayed without delaying the entire project Slack = LS − ES or Slack = LF − EF

Answer 13

CPM assumes we know a fixed time estimate for each activity and there is no variability in activity times PERT uses a probability distribution for activity times to allow for variability

Answer 14

Optimistic time (a) – if everything goes according to plan Pessimistic time (b) – assuming very unfavorable conditions Most likely time (m) – most realistic estimate

Answer 15

Total project completion times follow a normal probability distribution Activity times are statistically independent

Answer 16

The amount by which an activity is crashed is, in fact, permissible Taken together, the shortened activity durations will enable us to finish the project by the due date The total cost of crashing is as small as possible

Answer 17

Especially useful when scheduling and controlling large projects Straightforward concept and not mathematically complex Graphical networks help highlight relationships among project activities Critical path and slack time analyses help pinpoint activities that need to be closely watched Project documentation and graphics point out who is responsible for various activities Applicable to a wide variety of projects Useful in monitoring not only schedules but costs as well

Answer 18

Project activities have to be clearly defined, independent, and stable in their relationships Precedence relationships must be specified and networked together Time estimates tend to be subjective and are subject to fudging by managers There is an inherent danger of too much emphasis being placed on the longest, or critical, path