1. Chapter 4 MIS Project Management Lecturer Sihem Smida Sihem Smida Developing a project plan

2. 6–26–2 Developing the Project Plan محذوفة The Project Network –A flow chart that graphically depicts the sequence, interdependencies, and start and finish times of the project job plan of activities that is the critical path through the network. Provides the basis for scheduling labor and equipment. Enhances communication among project participants. Provides an estimate of the project’s duration. Provides a basis for budgeting cash flow. Identifies activities that are critical. Highlights activities that are “critical” and can not be delayed. Help managers get and stay on plan.

3. 6–36–3 Constructing a Project Network Terminology –Activity: an element of the project that requires time. –Merge Activity: an activity that has two or more preceding activities on which it depends. –Parallel (Concurrent) Activities: Activities that can occur independently and, if desired, not at the same time. A C DB

4. 6–46–4 Constructing a Project Network (cont’d) محذوفة Terminology –Path: a sequence of connected, dependent activities. –Critical path: the longest path through the activity network that allows for the completion of all project- related activities; the shortest expected time in which the entire project can be completed. Delays on the critical path will delay completion of the entire project. ABD (Assumes that minimum of A + B > minimum of C in length of times to complete activities.) C

5. 6–56–5 Constructing a Project Network (cont’d) Terminology –Event: a point in time when an activity is started or completed. It does not consume time. –Burst Activity: an activity that has more than one activity immediately following it (more than one dependency arrow flowing from it). Two Approaches –Activity-on-Node (AON) Uses a node to depict an activity. –Activity-on-Arrow (AOA) Uses an arrow to depict an activity. B D A C

6. 6–66–6 Basic Rules to Follow in Developing Project Networks محذوفة 1.Networks typically flow from left to right. 2.An activity cannot begin until all preceding connected activities are complete. 3.Arrows indicate precedence and flow and can cross over each other. 4.Each activity must have a unique identify number that is greater than any of its predecessor activities. 5.Looping is not allowed. 6.Conditional statements are not allowed. 7.Use common start and stop nodes.

7. 6–76–7 Network Computation Process محذوفة Forward Pass—Earliest Times –How soon can the activity start? (early start—ES) –How soon can the activity finish? (early finish—EF) –How soon can the project finish? (expected time—ET) Backward Pass—Latest Times –How late can the activity start? (late start—LS) –How late can the activity finish? (late finish—LF) –Which activities represent the critical path? –How long can activity be delayed? (slack or float—SL)

8. 6–86–8 Forward Pass Computation محذوفة Add activity times along each path in the network (ES + Duration = EF). Carry the early finish (EF) to the next activity where it becomes its early start (ES) unless… The next succeeding activity is a merge activity, in which case the largest EF of all preceding activities is selected.

9. 6–96–9 Backward Pass Computation محذوفة Subtract activity times along each path in the network (LF - Duration = LS). Carry the late start (LS) to the next activity where it becomes its late finish (LF) unless The next succeeding activity is a burst activity, in which case the smallest LF of all preceding activities is selected.

10. 6–10 Determining Free Slack (or Float) محذوفة Free Slack (or Float) –Is the amount of time an activity can be delayed after the start of a longer parallel activity or activities. –Is how long an activity can exceed its early finish date without affecting early start dates of any successor(s). –Allows flexibility in scheduling scarce resources. Sensitivity –The likelihood the original critical path(s) will change once the project is initiated. –The critical path is the network path(s) that has (have) the least slack in common.

11. Project Management Example: General Foundry Inc. محذوفة Have 16 weeks to install a complex air filter system on its smokestack May be forced to close if not completed w/in 16 weeks due to environmental regulations Have identified 8 activities

13. AON Network for General Foundry

14. Activity Time Estimates

15. Determining the Project Schedule محذوفة Some activities can be done simultaneously so project duration should be less than 25 weeks Critical path analysis is used to determine project duration The critical path is the longest path through the network

16. Critical Path Analysis محذوفة Need to find the following for each activity: Earliest Start Time (EST) Earliest Finish Time (EFT) Latest start time (LST) Latest Finish Time (LFT)

17. EFT Rule: EFT = EST + activity time Node Notation:

18. Forward Pass: Earliest Start and Finish Times

19. LST Rule: LST = LFT – activity time

20. Slack Time and Critical Path(s) محذوفة Slack is the length of time an activity can be delayed without delaying the project Slack = LST – EST Activities with 0 slack are Critical Activities The Critical Path is a continuous path through the network from start to finish that include only critical activities

21. Project Schedule and Slack Times

22. Critical Path and Slack Times

23. Total Slack Time vs. Free Slack Time محذوفة Total slack time is shared by more than 1 activity Example: A 1 week delay in activity B will leave 0 slack for activity D Free slack time is associated with only 1 activity Example: Activity F has 6 week of free slack time

24. Variability in Activity Times محذوفة Activity times are usually estimates that are subject to uncertainty Approaches to variability: 1.Build “buffers” into activity times 2.PERT – probability based 3.Computer simulation

25. PERT Analysis محذوفة Uses 3 time estimates for each activity Optimistic time (a) Pessimistic time (b) Most likely time (m) These estimates are used to calculate an expected value and variance for each activity (based on the Beta distribution)

26. Expected activity time (t) t = (a + 4m + b) 6 Variance = [ (b – a) / 6 ] 2 Standard deviation = SQRT(variance) = (b – a) 6

27. 27 Activity Information A 1232 0,111 B 234 3 0.111 C 12320.111 D 24640.444 E 14741.000 F 12931.778 G 341151.778 H 12320.111 Time estimates (wks)Mean Time Variance Activitya m b t  2

28. 6–28 [2, 0.111] [3, 0.111] [3, 1,778] [4, 0.444] [2, 0.111] [4, 1.000] [5, 1,778] Network Diagram with Expected Activity Times and Variances

29. 6–29 Earliest start / Earliest Finish 0 2 0 3 2 4 4 8 4 7 13 15 8 13 3 7 0

30. 6–30 Latest start / Latest Finish 0 2 1 4 2 4 4 8 10 13 13 15 8 13 4 8 0

31. Project Variance and Standard Deviation Project variance (σ p 2 ) = ∑ ( variances of all critical path activities) σ p 2 = 0.11 + 0.11 + 1.0 + 1.78 + 0.11 = 3.11 Project standard deviation (σ p ) = SQRT (Project variance) σ p = SQRT ( 3.11) = 1.76

32. Probability of Project Completion What is the probability of finishing the project within 16 weeks? Assumptions: – Project duration is normally distributed – Activity times are independent Normal distribution parameters: μ p = expected completion time= 15 weeks σ p = proj standard deviation = 1.76 weeks

33. 33 Probabilistic Network Analysis Determine the probability that a project is completed (project completion time is ) within a specified period of time within a specified period of timewhere  = t p = project mean time  = project standard deviation x = project time (random variable) Z = number of standard deviations of x from the mean (standardized random variable)  the mean (standardized random variable)  Z = x -  

34. Normal Probability Calculations Z = (Target time – expected time) σ p Z = (16 - 15) = 0.57 1.76 This means 16 weeks is 0.57 standard deviations above the mean of 15 weeks.

35. Probability Based on Standard Normal Table Prob (proj completion < 16 weeks) = 0.7158

36. Project Duration for a Given Probability What project duration does General Foundry have a 99% chance of completing the project within? i.e. Prob (proj duration < ? ) = 0.99 From Std. Normal Table, this corresponds to Z = 2.33

37. Z = (? - 15) = 2.33 1.76 So ? = 15 + 2.33 x 1.76 = 19.1 weeks

38. 6–38 Practical Considerations Network Logic Errors Activity Numbering Use of Computers to Develop Networks Calendar Dates Multiple Starts and Multiple Projects

39. Project Time Management Processes Activity definition: identifying the specific activities/tasks that the project team members and stakeholders must perform to produce the project deliverables Activity sequencing: identifying and documenting the relationships between project activities Activity resource estimating: estimating how many resources a project team should use to perform project activities Activity duration estimating: estimating the number of work periods that are needed to complete individual activities Schedule development: analyzing activity sequences, activity resource estimates, and activity duration estimates to create the project schedule Schedule control: controlling and managing changes to the project schedule 39 Project Time Management

40. Activity Lists and Attributes An activity list is a tabulation of activities to be included on a project schedule that includes: –The activity name –An activity identifier or number –A brief description of the activity Activity attributes provide more information such as predecessors, successors, logical relationships, leads and lags, resource requirements, constraints, imposed dates, and assumptions related to the activity 40 Project Time Management

41. Step1: activity definition Work breakdown structure and dictionary Project scope statement Project management plan Decomposition Templates Level of detail Expert judgement Inputs OutputsTools & Techniques Activity list Work breakdown structure and dictionary (updates) Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control

42. Step2: activity sequency Precedence Diagramming Method (PDM) Arrow Diagramming Method (ADM) Schedule network templates Dependency determination. Inputs OutputsTools & Techniques Project schedule network diagrams Activity list (updates) Project management plan and scope statement (updates) Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control Activity list Project scope statement

43. Step3: activity resource estimating Expert judgement Alternative identification Published estimating data Estimating software programs Bottom-up estimates by activity Inputs OutputsTools & Techniques Activity resource requirements Resource requirements supporting detail Activity list (updates) Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control Activity list Activity list attributes Organizational policies Resource availability

44. Step4: activity duration estimating Expert judgements analogous duration estimating quantitatively based durations three-point-estimates of duration reserve time maximum activity duration Inputs OutputsTools & Techniques Activity duration estimates Activity list (updates) Activity list attributes (updates) Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control Activity list Activity list attributes Project scope statement Project cost estimates Activity resource requirements Resource availability Organizational process assets Risk register

45. Step5: schedule development Expert judgements analogous duration estimating quantitatively based durations three-point-estimates of duration reserve time maximum activity duration Inputs OutputsTools & Techniques Critical path method Schedule compression Resource leveling Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control Project scope statement Project schedule network diagrams Activity duration estimates Activity resource requirements Resource availability Risk register Activity list attributes Resources calendars

46. Step6: schedule control Progress reporting schedule charge control system performance measurement project management software variance analysis schedule comparison bar charts Inputs OutputsTools & Techniques Project scheduel (updates) Requested changes Recommended corrective action Organizational process assets Activity definition Activity sequency Activity resource estimating Activity duration estimating Schedule development Schedule control Project schedule Performance reports Approved change requests management plan