1. Chapter 6 Allocating Resources to the Project

2. Introduction Projects compete with each other for resources
If resource is used but not consumed, which project must wait to use resource
If resource is consumed during use, may not be available for other projects or other projects must wait for replacement
In either case, one project must wait
One project is delayed
Likewise, different activities on the same project may compete for resources
Trade-offs must be made

3. Expediting a Project (Assumptions)
Smaller problem to avoid unnecessary arithmetic
Problem set in a deterministic world
All estimates of task duration are based on normal (or standard) resource loadings

4. Expediting a Project (Approaches)
The critical path method
Fast-tracking a project
Project expediting in practice
Opportunities before the project begins
Opportunities when the project is underway

5. The Critical Path Method
Normal duration estimates
Normal costs
Crash duration estimates
Crash costs
Crash cost per day

6. Notes on Crashing
Important to make sure the resources required to crash the project are available
Technology may be used to crash an activity
Using Ditch Witch to dig a ditch rather than adding more workers
May have to expedite tasks not on critical path to make resources available to other projects
Some tasks cannot be crashed

7. How to Crash Start with the normal schedule
Select activities to crash, one at a time
Focus on the critical path(s)
Select least expensive activity to crash
Calculate slope information on activities to crash

8. An Example of a Normal/Crash Project
Table 6-1

9. A PERT/CPM Example of Crashing a Project, AOA Network Part 1
Figure 6-1 (Partial)

10. A PERT/CPM Example of Crashing a Project, AOA Network Part 2
Figure 6-1 (Partial)

11. CPM Crash Cost-Duration History
Figure 6-2

12. Fast-Tracking a Project
An expediting technique in which one phase of the project is started before preceding phases are completed
Used in the construction industry when the building phase is started before the design and planning phases are complete
This technique is particularly appropriate when large proportion of work is routine

13. Project Expediting in Practice
Project manager may know ahead of time that this project is time-critical and needs to be finished as early as possible
Project manager may during project that it needs to be finished earlier
Something delays the project and time needs to be made up

14. Opportunities Before the Project Begins
Most projects have one time estimate
Many projects have a project “buffer”
A project time contingency may be added as well
Can monitor key activities closely
May order long-lead time items early

15. Opportunities When the Project Is Underway
Focus on critical path
Use contingency time
Pull resources from less critical activities
Move buffers to more critical activities
May skip less critical steps
May postpone activities involving non-core members
Move activities to post-project phase
May run activities in parallel or use weekends
Pressuring team to work faster
Get additional resources for overtime or more people
May reduce scope
May wait and see

16. Resource Loading
Refers to the amounts of specific resources that are scheduled for use on specific activities or projects at specific time
It is usually presented in the form of a list or table
Will see using short documentary DVD example

17. Project Plan and Gantt Chart for Production of a Short Documentary Film
Figure 6-3 17

18. Gantt Chart for DVD Project, Adjusted for Client Availability
Figure 6-4 18

19. Resource Loading Chart for DVD Production
Table 6-3 19

20. Resource Loading Issues
Most project management software assumes that any resource assigned to an activity will work on that activity 100 percent of the time available
Can be resolved by allocating a specific percentage of time to project
It is easy to over utilize human resources
Overtime is expensive

21. Resource Leveling
To perform resource leveling, software will move activities so that resources do not exceed their capacity
Using available slack first
Extending project duration where using slack does not work
Project manager may not try to level all resources
A working schedule may require more resources
A more-or-less steady state demand for human resources is highly desirable

22. Resource Over Allocation Report for Scriptwriter Showing All Activities
Figure 6-5 22

23. Graphic Resource Over Allocation Report for Scriptwriter
Figure 6-6

24. Resource Leveled Report for Scriptwriter Showing All Activities
Figure 6-7 24

25. Graphic Resource Leveled Report for Scriptwriter
Figure 6-8

26. Daily Resource Loading Chart for Scriptwriter Leveled
Table 6-4 26

27. Final Gantt Chart Schedule, Scriptwriters and Producer Leveled
Figure 6-9 27

28. Resource Loading/Leveling and Uncertainty
Holidays, vacations, sick days can reduce human resource availability
Not all required facilities and equipment will be available when needed
There may be change orders
All of these must be factored into plans

29. Allocating Scarce Resources to Projects
Leveling resources using slack is often not possible
Software needs instructions about what priority to use when allocating scare resources
When demand exceeds supply, software assigns a resource according to some priority rule selected by project manager
The key problem is deciding which activities gets the scare resource and in what order

30. Some Priority Rules As soon as possible As late as possible
Shortest task duration first
Minimum slack first
Most critical followers
Most successors
Most resources first 30

31. Allocating Scare Resources to Several Projects
When the allocating scarce resources is extended to where several projects are being carried out concurrently, the size and complexity of the problem increase
However, the nature of the underlying problem remains the same
There is a decided advantage if several projects are joined as a set
With several projects, we can link them together with pseudoactivities

32. Pseudoactivities
Pseudoactivities are those which have duration but require no resources
The use of pseudoactivities allows a set of projects to be linked and dealt with as though it were a single project
The individual projects are interrelated by specifying predecessor/successor relationships in Microsoft Project
They appear to Project to be parts of one project
Allows use of Microsoft Project resource loading and leveling charts and tables 32

33. Multiple Projects Connected with Pseudoactivities
Figure 6-11

34. Criteria of Priority Rules
Project manager faces the problem of choosing between different outcomes that result from different priority rules
Must also deal with different arrangements and durations of pseudoactivities
There are many measurable criteria to help select a priority rule
Schedule slippage: amount project or set of projects delayed by application of a leveling rule
Resource utilization: extent to which resources are over or underworked
In-process inventory: amount of unfinished work in the system

35. The Basic Approach
Basic approach is borrowed from a manufacturing model
There is a set of activities for one or more projects to be processed by a limited number of resources
Not all activities require the same resources
Some activities have higher priorities
Some activities need more work than others
Some activities must be done before others
Activity start times not known exactly
Activity processing times not know exactly

36. Resource Allocation and the Project Life Cycle
Scheduling method uses rule to assign scare resources to activities
Starts with most urgent and works down
Process continues until no more activities quality
If scarce resource is depleted before all non-critical activities are loaded, they go unsupplied
They then become a higher priority in later periods

37. Resource Allocation and the Project Life Cycle Continued
What happens if scare resource is depleted before all critical activities are assigned
May borrow from another ongoing activity with slack
May even deschedule the activity
Can use knowledge of the project’s life cycle to help make the decision

38. Project or Task Life Cycles
Figure 6-12

39. Goldratt’s Critical Chain
Projects are completed faster when there are fewer of them struggling for attention from a limited set of facilities
Goldratt’s focus in the Critical Chain is on a single project with multiple demands on a scarce resource
The logic extends to the multiproject case without alteration
Resource usage and project schedules are inextricably bound together
The technological necessities that force schedules to be ordered in specific ways simultaneously force resources to be used in specific ways

40. Project Issues Project due dates are too often unrealistic
There are too many changes made in the project’s scope
Key resources and data are often unavailable when needed
The budget is frequently unrealistic and therefore often exceeded
It seems like my project is always in competition for resources with other projects

41. Critical Chain Continued
It is not farfetched to conclude that the causes of these problems are generic to all types of projects
Problems encountered when managing projects are strongly related to the need to trade off one project objective for another
To what extent is the need to make these trade-offs are caused by human decisions and practices
In other words, can more effective project management minimize the occurrence of these problems?
Will examine the complaint regarding unrealistic due dates in more detail

42. Three Project Scenarios
Figure 6-13 42

43. How Long? Each task takes 10 days
What is the completion time for each project?
All three would have the same duration of 50 days
Simple project with five tasks takes the same time as complex one with 11 tasks!

44. Part of Problem
Part of the problem is the assumption that the activity times are known with certainty
Assume all activities are normally distributed
Mean of 10
Standard deviation of three
Each is simulated 200 times

45. Project Completion Time Statistics Based on Simulation
Table 6-5

46. Analysis
This example clearly demonstrates how the commonly made assumption of known activity times in practice can lead to quite unrealistic project deadlines
The results would have been even more dramatic had the activities required some common resources
Similarly, the results would have been more dramatic and realistic had a nonsymmetrical distribution been used to model the activity times

47. Estimating Task Times Workers often pad time estimates
Inflated time estimates tend to create even more problems
When workers finish a padded activity early, they often do not let management know they are done yet
Worse, workers may perceive they have plenty of time to complete the task and therefore delay starting the task
Goldratt refers to this as the student syndrome

48. Multitasking
Multitasking is assigning team members to multiple projects and having them allocate their time across these projects
There is typically a penalty or cost associated with switching from working on one project to another

49. Sample Project with Multitasking
Figure 6-16

50. Alternative Gantt Charts for Projects A and B
Figure 6-17

51. Common Chain of Events
Assuming that activity times are known and that the paths are independent leads to underestimating the actual amount of time needed
Because the time is underestimated, project team members tend to inflate their time estimates
Inflated time estimates lead to work filling available time, workers not reporting that a task has been completed early
An important caveat then becomes that safety time is usually visible to project workers and is often misused
Misused safety time results in missed deadlines and milestones

52. Common Chain of Events Continued
Hidden safety time further complicates the task of prioritizing project activities
The lack of clear priorities likely results in poor multitasking
Task durations increase as a result of poor multitasking
Uneven demand on resources may also occur as a result of poor multitasking
In an effort to utilize all resources fully, more projects will be undertaken to make sure that no resources are underutilized
Adding more projects further increases poor multitasking

53. Resolving These Problems
Goldratt suggests that the key to resolving this is to schedule the start of new projects based on the availability of bottleneck resources
He further suggests that time buffers be created between the bottleneck resource and the resources that feed it
He also suggests reducing the amount of safety time added to individual tasks and then adding some fraction of the safety time reduced back into the system as safety buffer for the entire project

54. The Critical Chain
Another limitation is the dependency between resources and tasks is often ignored
Using traditional approaches, A1-C1 is the critical path
What if A1 and A2 are not independent
Then page A1-C1 increases to 22 days

55. Addressing Problem
Need to consider both precedence relationships and resource dependencies
Goldratt proposes thinking in terms of the longest chain of consecutively dependent tasks where such dependencies can arise
Referred to as critical chain
There are two potential sources that can delay the project
Delay in the tasks that make up the critical chain
Delay in activity feeding the critical chain that results in delay of the critical chain

56. Project and Feeder Buffers
Figure 6-19

57. Copyright
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information herein.