1

Precedence Diagramming

2

Work Breakdown Structure (WBS)•A deliverable oriented hierarchical decomposition of the work to be executed by the project team to accomplish the team mission and create the required deliverables. The WBS defines the project scope.

Scheduling Terminology

Team Mission

3

Deliverable•Any unique and verifiable product or result that must be produced to complete a project. Usually the lowest level of the WBS.

Scheduling Terminology

Team Mission

4

Scheduled Activity (task)•A component of work performed to create a deliverable.

Scheduling Terminology

Team Mission

Task 1Task 2(Etc.)

Task 1Task 2(Etc.)

Task 1Task 2(Etc.)

Task 1Task 2(Etc.)

Task 1Task 2(Etc.)

Task 1Task 2(Etc.)

WB

S(S

cope

)A

ctiv

ity L

ist

(Sch

edul

e)

5

Duration•Total number of work periods required to complete a scheduled activity. Usually expressed as workdays. (contrast with “effort”)

•Effort•Total number of labor units requird to complete a scheduled activity. Usually expressed as staff hours or a rate. (contrast with “duration”)

•Schedule Milestone•A significant event in the project schedule, such as an event restraining future work or marking the completion of a major deliverable. A “measuring point”. Milestones have “0” (zero) duration and no resource assignments.

Scheduling Terminology

6

Basic Bar Chart (Gantt Chart)

7

Defining Activities/Tasks

•Definition

•Assignment

•Significance

8

Task Interdependencies Specify Task Relationships

All tasks are Related To:• Other Schedule Activities

– “Mandatory” or “Hard Logic”– “Discretionary” or “Soft

Logic”

• External Events– Dependent Dates– Required Dates Network Diagram

Task Interdependencies

9

• FS – Finish Start

Start

Finish

• SS – Start Start

• FF – Finish Finish

Start

Finish

Types of Task Relationships

Finish Start

10

• Lead and Lag are used to Modify Relationships• Lead and Lag Can be used with any

Relationship Type (FS, FF, SS)

NormalFinish - Start

Leads and Lags

Finish – StartModified by a Lead

Finish – StartModified by a Lag

11

Arrow Diagram Method (ADM)

(aka Activity on Arrow – AOA)•Tasks represented by arrows (length not related to duration)

•Dependency shown as node

•Only F-S relationship used

•Archaic – not used with current software

1

2

6

7

83

5

4

“Dummy task” used to complete logic, duration of “0”

12

Precedence Diagram Method (PDM)

(aka Activity on Node – AON and Network Diagram)•Tasks represented by nodes

•Dependency shown as arrows or links between nodes

•All task relationships can be used (FS, FF, SS)

•Basis for all current software applications

A

B

C

D

E

F

G

13

Critical Path•Sequence of scheduled activities that determines the project duration

•Longest duration path through the project network

•Activities on the Critical Path are called “Critical Activities”

•Critical activities have no float or slack

•A project can have more than one critical path

•Activities not on the Critical Path are called “Non Critical Activities

•To shorten the project duration, a scheduler must modify the critical path activities or dependencies

14

•Total Float – the total amount of time that a scheduled activity (or milestone) may be delayed or extended without delaying the project end date or violating a schedule constraint.

•Free Float – the amount of time that a scheduled activity (or milestone) can be delayed without delaying the start of the next activity in the network.

•Negative Float – the amount of time that by which a critical activity (or milestone) misses a required date.

Float (or Slack)

15

Critical Path Method

1. Calculate Early Start & Early Finish dates (FORWARD PASS)

2. Calculate Late Start & Late Finish dates (BACKWARD PASS)

3. Calculate TOTAL FLOAT for each activity

4. Identify activities with 0 (zero) TOTAL FLOAT

16Activity Node

WBS Code Activity

Late Start (LS)

Late Finish (LF)

Early Start (ES)

Early Finish (EF)

Total Float (TF)

Duration

17

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Simple Project consisting of 5 Tasks

18

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

TWO THINGS NEEDED TO SET PROJECT START DATE

1. First and last activities (milestones)

2. Activity durations

1

19

Critical Path Method

1. Calculate Early Start & Early Finish dates (FORWARD PASS)

2. Calculate Late Start & Late Finish dates (BACKWARD PASS)

3. Calculate TOTAL FLOAT for each activity

4. Identify activities with 0 (zero) TOTAL FLOAT

6

20

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Project Start Date & Task Durations are known

1

21

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Early Finish = Early Start + Duration

18

22

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Early Start With Single Predecessor

18

8

8

13

10

23

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Early Start With Multiple Predecessors

18

8

8

13

10

1316

24

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Start-to-Start Relationships (A to E)

18

8

8

13

10

1316

14

25

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Completed FORWARD Pass

18

8

8

13

10

1316

14

26

Critical Path Method

1. Calculate Early Start & Early Finish dates (FORWARD PASS)

2. Calculate Late Start & Late Finish dates (BACKWARD PASS)

3. Calculate TOTAL FLOAT for each activity

4. Identify activities with 0 (zero) TOTAL FLOAT

27

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Start the BACKWARD Pass

18

8

8

13

10

1316

14

16

The last activity Early Finish (EF) will default to be the Late Finish (LF).

28

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Late Start (LS) = Late Finish (LF) - Duration

18

8

8

13

10

1316

14

1613

29

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Late Starts with Single Successors

18

8

8

13

10

1316

14

1613

13

1311

8

30

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Late Start with Multiple Successors

18

8

8

13

10

1316

14

1613

13

13

8

11

81

31

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Finish-to-Finish Relationships (D to E)

18

8

8

13

10

1316

14

1613

13

13

8

11

81

1613

32

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Completed BACKWARD Pass

18

8

8

13

10

1316

14

1613

13

13

8

11

81

1613

33

Critical Path Method

1. Calculate Early Start & Early Finish dates (FORWARD PASS)

2. Calculate Late Start & Late Finish dates (BACKWARD PASS)

3. Calculate TOTAL FLOAT for each activity

4. Identify activities with 0 (zero) TOTAL FLOAT

6

34

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Total Float (TF) = Late Finish (LF) – Early Finish (EF)

18

8

8

13

10

1316

14

1613

13

13

8

11

81

1613

0

0

0

12

3

35

Critical Path Method

1. Calculate Early Start & Early Finish dates (FORWARD PASS)

2. Calculate Late Start & Late Finish dates (BACKWARD PASS)

3. Calculate TOTAL FLOAT for each activity

4. Identify activities with 0 (zero) TOTAL FLOAT

6

36

Activity AWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

7

Activity BWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

5

Activity CWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

2

Activity DWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Activity EWBS Code Activity

Early Start (ES)

Early Finish (EF)

Late Start (LS)

Late Finish (LF)

Duration

Total Float (TF) =

3

Critical Path – Tasks with no Total Float (TF)

18

8

8

13

10

1316

14

1613

13

13

8

11

81

1613

0

0

0

12

3

37

Task A2 days

Task B3 days

Task C1 days

Task D2 days

Task E4 days

Task F5 days

Task G2 days

StartFin

St – A – C – F – Fin: ________

St – B – D – G – Fin: ________

St – B – E – G – Fin: ________

8 days

7 days

9 days

38

Task A4 days

Task B6 days

Task D5 days

Task E10 days

Task F5 days

Task H7 days

Task J2 daysStart Fin

Task C8 days Task G

8 days

St – A – D – H – Fin: ________

St – B – E – J – Fin: ________

St – C – F – J – Fin: ________

St – C – G – Fin: ________

16 days

18 days

15 days

16 days

39

Activity Duration Preceding Activity

Start (Milestone) 0 --

Task A 4 days Start

Task B 3 days Start

Task C 5 days Task A

Task D 7 days Task B

Task E 3 days Task B

Task F 10 days Task C & Task D

Task G 4 days Task D & Task E

Task H 2 days Task E

Task I 2 days Task F & Task G

Task J 4 days Task H

Finish (Milestone) 0 Task I & Task J

40

St – A – C – F – I – Fin: ________

St – B – D – F – I – Fin: ________

St – B – D – G – I – Fin: ________

St – B – E – G – I – Fin: ________

St – B – E – H – J – Fin: ________

12 days

16 days

22 days

21 days

Task C5 daysTask A

4 days

Start

Fin

Task B3 days

Task D7 days

Task E3 days

Task F10 days

Task G4 days

Task H2 days

Task J4 days

Task I2 days

12 days