PM Resource Leveling

8/10/2019 PM Resource Leveling

1/17

Scheduling With Constrained

Resources

So far have assumedall resources required for

project will be available.

Q: Will they be available? What happens if theyare not?


2/17

Resource Loading

Resource Loading: amount of a specifiedresource required throughout a project

Assume have a well-defined project

Have defined the kinds of resourcesand amount or numberof

resources for every work package


3/17

Resource Loading Analysis:

apply to constrainedresources

Example: Work Package D resource requirements:

Programmer 160 hrs.

Systems Analyst 40 hrs.

Mainframe Computer 10 hrs.

Suppose Systems Analyst time and Mainframe Computer time, no

problem. Hence, ignore thesein resource loading analysis.

Programmers are very busy and in short supply.

Hence, focus on this in resource loading analysis


4/17

Resource Loading Analysis (contd)

Assume

Work Package D must be completed in 2 weeks

Each programmer can devote at most 20 hrs per week.

Thus, the required programmers for Work Package D:

160 hrs

2 wks20

80 hrs. 80 4 programmerswk

wkwk hrs

hrs

programmer

= =

Work Package D will require 4 programmers for two weeks

Similar estimates are made for number of programmers for every

work package in the project


5/17

Activity

Immediate

Predecessors

Time

(weeks)

Resource

(Programmers)A --- 2 3

B --- 3 8

C --- 2 6

D --- 2 4

E A 4 9

F C 2 7

G D, F 3 2

H B, G 4 1

B

D

H

F G

E

C

A

Start

End

Project Network


6/17

Resource Loading Analysis

Questions:

According to the schedule, how many programmers will

be needed each week for the project?

Given the shortage of programmers, will there be

enough programmers for the project?


7/17

Gantt Chart, early times

1 2 3 4 5 6 7 8 9 10 11

CP

A, 3 E, 9

B, 8

C, 6 F, 7 G, 2 H, 1

D, 4

Key:

e.g., Activity D requires 4 programmers

According to the schedule, how many programmers will

be needed each week for the project?


8/17

24

1 2 3 4 5 6 7 8 9 10 11

A

E

B

C

F

G

H

D

24

22201816141210

8642

B

F

G

21

16

11

2 1

E

Resource Loading Diagram

Early Times

A, 3 E, 9

B, 8

C, 6 F, 7 G, 2 H, 1D, 4

1 2 3 4 5 6 7 8 9 10 11

Gantt Chart

For example, during weeks 1 and 2

Activities A, B, C, and D are

scheduled

So, number of programmers needed is

3 + 8 + 6 + 4 = 21

In week 3

Activities E, B, and F are scheduled

So, 9 + 8 + 7 = 24

(Most project management software perform this kind of analysis)


9/17

Resource Leveling

What happens if required resources exceed the

available amount?

Use resource leveling technique


10/17

Resource Leveling (contd)

1 2 3 4 5 6 7 8 9 10 11

A

E

B

C

F

G

H

D

24

22

20

18

1614

12

10

8

6

4

2B

F

G

2124

16

2 1E

Resource Loading using

Early Event Times

week

The schedule is infeasiblesince

weeks 1-4 require more than 12

programmers

Suppose maximum number of

programmers available forproject in any given week = 12


11/17


Many activities are scheduled early in the project

Not all of these haveto be scheduled then

They can be delayed

Delaying activities defers need for resources


12/17

1 2 3 4 5 6 7 8 9 10 11 12

A* E*

B*

C F G H

D

Use trial and error, delay activities along their slack ties, check impacton total required resources.

*For example, delay

A by 2 weeks

B by 4 weeks

E by 5 weeks


13/17

Resource Leveling Viola!

Project can be completed in 11 weeks with no more than10 programmers per week

*Resource loading after rescheduling A, B, and E

1 2 3 4 5 6 7 8 9 10 11

C

D

G

10

8

6

4

2

FE*

H

Program

mers

A*

B*

B*

C F G H

D

A* E*


14/17


Method is called resource leveling because it results in

leveling of peak requirements

Notice in example, if constraint on programmers had

been less than 10, project would not be able to complete

project in 11 weeks

1 2 3 4 5 6 7 8 9 10 11

C

D

G

108642

F

E*

H

A*B*


15/17


When project has multiple constrained resources,

Repeat same analysis for each

All resources must be leveled simultaneously so no

resource exceeds constraints This is one application in which project management

software that is invaluable

When PM does not have direct authority over resources

Speak to managers of resources. Try to get suggestions abouthow to meet schedule with limited resources.


16/17

Multi-Project Scheduling

Use similar approach to schedule multiple projects that share

constrained resources Create resource loadings for projects scheduled at same time.

Combined to yield multi-project loading.

AB

E

F

C

D

A

B

E

F

CD

Time

Tasks

Project A

Project B

Time


17/17

24222018161412108642

Project A

Project B

Multi-Project Scheduling

If loading exceeds constraints, tasks within projects are delayedalong their slack times.

If that fails, then tasks in lower-priority projects are delayed further or

(lower priority projects are delayed in their entirety) Software for multi-project planning and scheduling have this

capability

Documents

PM Resource Leveling