managing project processes managing project processes

Managing Managing ProjectProjectProcessesProcesses

Characteristics of a ProjectCharacteristics of a Project

• A unique, one-time effort

• Requires completion of a large number of interrelated activities

• Resources, such as time and/or money, are limited

• Typically has its own management structure

Critical Path Method (CPM)Critical Path Method (CPM)

• Designed to provide intense micro-control

• System is dynamic; it continues to provide periodic reports as project progresses

Manager’s View of CPMManager’s View of CPM

• List of project activitiesList of project activities• Precedence relationship among activitiesPrecedence relationship among activities• Estimate of each activity’s durationEstimate of each activity’s duration

• Estimated duration of projectEstimated duration of project• Identification of critical activitiesIdentification of critical activities• Amount of slack for each activityAmount of slack for each activity

CPM processing proceduresCPM processing procedures

CPM TerminologyCPM Terminology• Activity

– A task or certain amount of work required in the project

– Requires time to complete– Represented by an arc (AOA) or a node (AON)

• Dummy activity (AOA only)

– Indicates only precedence relationships– Does not require any time of effort

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CPM TerminologyCPM Terminology• Network

– Shows sequential relationships among activities using nodes and arrows

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CPM TerminologyCPM Terminology• Path

– Connected sequence of activities leading from starting event to ending event

• Critical path– Longest path (time); determines project

duration

• Critical activities– All of the activities that make up critical

path

CPM TerminologyCPM Terminology• Earliest start (ES)

– Earliest that an activity can begin; assumes all preceding activities have been completed

• Earliest finish (EF)– ES + activity time

• Latest finish (LF)– Latest that an activity can finish and not change

project completion time• Latest start (LS)

– LF - activity time

Steps in CPM AnalysisSteps in CPM Analysis

• Draw the CPM network– A graphic view of relationships among

required activities

• Path analysis– Determine length of each path (time

required to complete each path)– Longest path is the critical path

Steps in CPM AnalysisSteps in CPM Analysis• Network analysis

– Working from left to right, find the EF and ES for each activity

– Working from right to left, find LF and LS for each activity

– Compute activity’s slack• Total Slack = LS - ES = LF - EF • This slack is shared with other activities

– Free slack• Time an activity may be delayed without impacting the ES of

successor activities

St. Adolf’s HospitalSt. Adolf’s HospitalImmediate

Activity Description Predecessor(s)

ASelect administrative and medical staff.BSelect site and do site survey.CSelect equipment.DPrepare final construction plans and layout.EBring utilities to the site.FInterview applicants and fill positions in nursing,

support staff, maintenance, and security.GPurchase and take delivery of equipment.HConstruct the hospital.IDevelop an information system.JInstall the equipment.KTrain nurses and support staff.



ASelect administrative and medical staff.—BSelect site and do site survey.—CSelect equipment.ADPrepare final construction plans and layout.BEBring utilities to the site.BFInterview applicants and fill positions in nursing,

support staff, maintenance, and security.AGPurchase and take delivery of equipment.CHConstruct the hospital.DIDevelop an information system.AJInstall the equipment.E,G,HKTrain nurses and support staff.F,I,J



ASelect administrative and medical staff.—BSelect site and do site survey.—CSelect equipment.ADPrepare final construction plans and layout.BEBring utilities to the site.BFInterview applicants and fill positions in nursing,support staff, maintenance, and security.AGPurchase and take delivery of equipment.CHConstruct the hospital.DIDevelop and information system.AJInstall the equipment.E,G,HKTrain nurses and support staff.F,I,J

Completion Time

ImmediateActivity Description Predecessor(s)


St. Adolf’s HospitalSt. Adolf’s Hospital

Completion Time

Start

A12




Completion Time

Start

A12

B9




Completion Time

StartC

10

A12

B9




Completion Time

StartC

10

D10

A12

B9




Completion Time

StartC

10

D10

E24

A12

B9




Completion Time

Start

F10

C10

D10

E24

A12

B9




Completion Time

Start

F10

C10

D10

E24

G35

A12

B9




Completion Time

Start

F10

C10

D10

E24

G35

H40

A12

B9




Completion Time

Start

I15

F10

C10

D10

E24

G35

H40

A12

B9




Completion Time

Start

I15

F10

C10

D10

E24

G35

H40

J4

A12

B9




Completion Time

Start

K6

I15

F10

C10

D10

E24

G35

H40

J4

A12

B9




Completion Time

FinishStart

K6

I15

F10

C10

D10

E24

G35

H40

J4

A12

B9




Completion Time

FinishStart

K6

I15

F10

C10

D10

E24

G35

H40

J4

A12

B9

Path Expected Time (wks)

A-F-K 28A-I-K 33A-C-G-J-K 67B-D-H-J-K 69B-E-J-K 43


Earliest StartandEarliest Finish Times

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

I

15

F

10

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0

I

15

F

10

Earliest start time

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

Earliest start time Earliest finish time

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

0 9

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

9 33

0 9 9 19

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22

9 33

0 9 9 19

12 22FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22

19 59

9 33

0 9 9 19

12 22FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22

22 57

19 59

9 33

0 9 9 19

12 22FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22

22 57

59 6319 59

9 33

0 9 9 19

12 22FinishStart


Latest StartandLatest Finish Times

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

63 69 Latestfinishtime

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

63 69

Lateststarttime

Latestfinishtime

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

53 63 63 69

59 63

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

53 63 63 69

24 59

19 59

35 59

59 63

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

53 63 63 69

14 24 24 59

9 19 19 59

35 59

59 63

FinishStart



A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Earliest start time Earliest finish timeLatest start time Latest finish time

Critical path

FinishStart

St. Adolf’s HospitalSt. Adolf’s HospitalGantt Charts


Activity Slack Analysis

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

FinishStart



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish

Activity Slack



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish

Activity Slack

Slack = LS – ES

or

Slack = LF – EF



K

6

63 6963 69

Start

A

12

C

10

G

35

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22

22 57

19 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63

14 24 24 59

0 9 9 19 19 59

35 59

Activity Slack

SlackK = 63 – 63

or

SlackK = 69 – 69

J

4

59 6359 63

Finish



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish

Activity Slack

SlackK = 0

or

SlackK = 0



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish

Node Duration ES LS Slack



Start

A

12

K

6

C

10

G

35

J

4

H

40

B

9

D

10

E

24

0 12

I

15

F

10

12 27

12 22 63 69

22 57

59 6319 59

9 33

0 9 9 19

12 22

48 63

2 14 53 63 63 69

14 24 24 59

0 9 9 19 19 59

35 59

59 63

Finish


A 12 0 2 2B 9 0 0 0C 10 12 14 2D 10 9 9 0E 24 9 35 26F 10 12 53 41G 35 22 24 2H 40 19 19 0I 15 12 48 36J 4 59 59 0K 6 63 63 0


Critical Path

C

10

G

35

E

24

I

15

F

10

12 27

12 22

22 57

9 33

12 22

48 63

53 63

14 24 24 59

35 59

B

9

0 9

0 9

D

10

9 19

9 19

H

40

19 5919 59

J

4

59 6359 63

K

6

63 6963 69

Finish


A 12 0 2 2BB 99 00 00 00C 10 12 14 2DD 1010 99 99 00E 24 9 35 26F 10 12 53 41G 35 22 24 2HH 4040 1919 1919 00I 15 12 48 36JJ 44 5959 5959 00KK 66 6363 6363 00


Critical Path

C

10

G

35

E

24

I

15

F

10

12 27

12 22

22 57

9 33

12 22

48 63

53 63

14 24 24 59

35 59

B

9

0 9

0 9

D

10

9 19

9 19

H

40

19 5919 59

J

4

59 6359 63

K

6

63 6963 69

A

12

0 12

2 14

FinishStart

St. Adolf’s HospitalSt. Adolf’s HospitalActivity Slack

Program Evaluation andProgram Evaluation andReview Technique (PERT)Review Technique (PERT)• PERT is based on assumption that an

activity’s duration follows a probability distribution instead of being a single value.

• Probabilistic information about activities is translated into probabilistic information about project.

PERTPERT

• Three time estimates are required to compute parameters of an activity’s duration distribution:– Pessimistic time (b ) - time activity would

take if things did not go well

– Most likely time (m ) - consensus best estimate of activity’s duration

– Optimistic time (a ) - time activity would take if things did go well

Steps in PERT AnalysisSteps in PERT Analysis

• Draw network as in CPM• Analyze paths through network and find

critical path• Length of critical path is mean of project

duration probability distribution– assumed to be normal (really beta)

– 50% probability the project will be completed in this amount of time

Steps in PERT AnalysisSteps in PERT Analysis

• Standard deviation of project duration is computed by adding variances of critical activities (all activities that make up critical path) and taking square root of that sum

• Probability computations can now be made using normal distribution table

Calculating Probabilistic Calculating Probabilistic Activity TimesActivity Times• Three time estimates

– optimistic (a)– most likely (m)– pessimistic (b)

22

( 4 )

6

6

( )6

e

a m bt

b a

b a

a, m, and b Estimatesa, m, and b Estimates

PERT Example

Question

• What is the probability of completing the project within 23 weeks?

• Look up z value in normal distribution table – see page 457 in text

• Z=1.52 corresponds to area under the curve of .9357

• Probability project completes within 23 days equals .9357

• Probability project completes takes longer than 23 days equals .0643 (1.0 - .9357)

Project Life CycleProject Life Cycle

Definition and

organization

Planning Execution Close out

Start Finish

Res

ou

rce

req

uir

emen

ts

Time

Activity Cost-Time TradeoffsActivity Cost-Time Tradeoffs

• Project managers may have option or requirement to crash project, or accelerate completion of project.

• This is accomplished by reducing length of critical path(s).

• Length of critical path is reduced by reducing duration of activities on critical path.

Cost-Time Cost-Time TradeoffsTradeoffs• If each activity requires expenditure of an

amount of money to reduce its duration by one unit of time, then project manager selects least cost critical activity, reduces it by one time unit, and traces that change through remainder of network.

Cost-Time Cost-Time TradeoffsTradeoffs• As a result of a reduction in an activity’s

time, a new critical path may be created.

• When there is more than one critical path, each of the critical paths must be reduced.

• If length of project needs to be reduced further, process is repeated.

Computer Software Computer Software for Project for Project ManagementManagement• Artemis Views (Artemis Management Systems)

• FastTrack Schedule (AEC Software)• Microsoft Project (Microsoft Corp.)• Oracle Projects (Oracle Corp.)• PowerProject (ASTA Development)• Primavera Project Planner (Primavera Systems)• SuperProject (Computer Associates International)• TurboProject (IMSI)

Evaluation of Evaluation of CPM/PERTCPM/PERT

• Activities are assumed to be independent.• A precise breaking point where one activity ends

and another begins is also assumed.• Initially-critical activities might not receive attention

they deserve until it is too late.• Activity time estimates might be biased.• Cost of CPM/PERT might not be justified by value

of information it provides.• Employees might not understand statistical

underpinnings of PERT.

managing project processes managing project processes

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