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