Projmgmt-1/14 DePaul University Project Management I - Realistic Scheduling Instructor: David A....
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Transcript of Projmgmt-1/14 DePaul University Project Management I - Realistic Scheduling Instructor: David A....
Projmgmt-1/14
DePaul University
Project Management I - Realistic Scheduling
Instructor: David A. Lash
Projmgmt-2/14
From Project Definition
Project
Rules
ScopeDeliverables
PrePlanningRisk Management
- Develop Approach- Risk Management
Step 1Develop a WBS
All
Project
TasksStep 2
Sequence thetasks
Step 3Estimate the
work packages
Duration
Estimates
Step 4:Calculate an
initialschedule
Equi
pmen
t
requ
irem
ents
& la
bor &
ski
ll
estim
ates
Step 5:Assign & level
resources
Cr i
tica
lP
ath
, f l
oat
,m
iles
ton
es
Step 6DevelopBudget
Realistic schedule& forecast
No
n-l
abo
rco
sts
Realistic schedule
& forecast
Project Plan- all project task s
- schedule- responsibilities
- budgetResource forecase
All
Pro
ject
Tas
ks
Net
wd
iag
ram
s
Projmgmt-3/14
Sequencing Tasks
No Task Pred Res Dur
1 Acquire Lawnmaterial
Homeowner
2D
2 Remove Debris Teens& YthGroup
4D
3 Prepare Soil 1,2 Teens 4D4 Plaint lawn seed 3 Teens 1D5 Plant Shrubs 2 Teens 12D
•Either Task 1 or 2 can go first (Can be concurrent)•Task 5 can't start until 2•Task 3 needs 1 & 2•Task 4 needs 3 (therefore needs 1 & 2 too!)
Projmgmt-4/14
Finish
4
5
Start
1
2
3
Correct Network Diagram
•How get from network diagram to schedule?
Projmgmt-5/14
Step 4 - Calculate Initial Schedule
PERT Charts - Program, Evaluation & Review Technique - Calculate 4 variables:
– Early Start (ES) - The earliest date a task can BEGIN
– Early Finish (EF) - The earliest date a task can END
– Late Start (LS) - The latest date a task can BEGIN
– Late Finish (LF) - The latest date a task can END ID DUR
ES EF
LS LF
FL
Early Start
Early Finish
Late Finish
Late Start Float Days
Projmgmt-6/14
Step 4 - Diagram ES,EF, LS, LF, FL
ID DUR
ES EF
LS LF
FL
Early Start
Early Finish
Late Finish
Late Start Float Days
EarlyStart
DurationEarlyFinish
Late Start SlackLate
Finish
Task Name
Projmgmt-7/14
Step 4 - Calculate Initial Schedule
There are 3 major steps– Step 1 - Forward Pass - Determine the Early
Start (ES) and Early Finish (EF) for each task Works through tasks from start to finish
– Step 2 - Backward Pass - Determine the late start (LS) and late finish (LF) dates.
Works backward through tasks from end to start
– Step 3 - Calculate Float - Determine the schedule flexibility for each task.
Calculated by subtracting the ES from LS.
Projmgmt-8/14
Step 4 - Calculate Initial Schedule
Step 1 - Forward Pass - Work forward from the start to calculate ES and EF
Task 1 & 2 is assumed to be the first day of the project.
No Task Pred Res Dur
1 Acquire Lawnmaterial
Homeowner
2D
2 Remove Debris Teens& YthGroup
4D
3 Prepare Soil 1,2 Teens 4D4 Plaint lawn seed 3 Teens 1D5 Plant Shrubs 2 Teens 12D
ID DUR
ES EF
LS LF
FL
1 2D
1 2
LS LF
FL
2 4D
1 4
LS LF
FL
Projmgmt-9/14
Step 4 - Calculate Initial Schedule
Step 1 - Forward Pass - Calculate ES and EF
Task 5 finishes after task 2.
No Task Pred Res Dur
1 Acquire Lawnmaterial
Homeowner
2D
2 Remove Debris Teens& YthGroup
4D
3 Prepare Soil 1,2 Teens 4D4 Plaint lawn seed 3 Teens 1D5 Plant Shrubs 2 Teens 12D
ID DUR
ES EF
LS LF
FL
5 1`2D
5 16
LS LF
FL
2 4D
1 4
LS LF
FL
Projmgmt-10/14
Step 4 - Calculate Initial Schedule Step 1 - Forward Pass - Calculate ES and EF
Task 3 finishes after task 1 & 2. (4 after 3)
No Task Pred Res Dur
1 Acquire Lawnmaterial
Homeowner
2D
2 Remove Debris Teens& YthGroup
4D
3 Prepare Soil 1,2 Teens 4D4 Plaint lawn seed 3 Teens 1D5 Plant Shrubs 2 Teens 12D
ID DUR
ES EF
LS LF
FL
3 4d
5 8
LS LF
FL
2 4D
1 4
LS LF
FL
1 2D
1 2
LS LF
FL
4 1d
9 9
LS LF
FL
Projmgmt-11/14
Step 4 - Calculate Initial Schedule
3 4d
5 8
LS LF
FL
2 4D
1 4
LS LF
FL
1 2D
1 2
LS LF
FL
4 1d
9 9
LS LF
FL
Start
5 1`2D
5 16
LS LF
FL
Finish
Projmgmt-12/14
Step 4 - Calculate Initial Schedule
There are 3 major steps– Step 1 - Forward Pass - Determine the Early
Start (ES) and Early Finish (EF) for each task Works through tasks from start to finish
– Step 2 - Backward Pass - Determine the late start (LS) and late finish (LF) dates.
Works backward through tasks from end to start
– Step 3 - Calculate Float - Determine the schedule flexibility for each task.
Calculated by subtracting the ES from LS.
Projmgmt-13/14
Step 4 - Calculate Initial Schedule Backward Pass -
– Set Project Finish Date - Calculate the LS and LF dates
– Determine The Last Start for the last CP task (5)
Last finish is the minimal time = 16 The finish day = 16 therefore LS = 5
(16+1-12) = 5 if task 5 not start by day 5 the project
will be late
5 1`2D
5 16
5 16
FL
Finish
LSLF
Finishday is finish day ofproject(17)
Projmgmt-14/14
Step 4 - Calculate Initial Schedule
Backward Pass - – Take the next CP date (task 2). Find LS
The finish day = 4 therefore LS is 1 (4+1-4).
If task 2 not start by day 1 the project will be late!
5 1`2D
5 16
5 16
FL
Finish
LSLF
Finishday is start date of next task.
2 4D
1 4
1 4
FL
Projmgmt-15/14
Step 4 - Calculate Initial Schedule
Backward Pass - (Repeat for non - CP items)– Start with last non-CP task (task42).
Find LF - For task 4 with dur=1 LF=16 Find LS = 12 (15+1-1). If task 4 not started on day 16 will be late! If task 3 not start on day 12 will be late!
Finish
LS
LF
Finishday is start date of next task.
3 4d
5 8
12 15
FL
1 2D
1 2
10 11
FL
4 1d
9 9
16 16
FL
LF = 15 latest it can finishLS = 15+1 -5 = 11 - latest it can start
Projmgmt-16/14
Step 4 - Calculate Initial Schedule
3 4d
5 8
12 15
FL
2 4D
1 4
1 4
FL
1 2D
1 2
10 11
FL
4 1d
9 9
16 16
FL
Start
5 1`2D
5 16
5 16
FL
Finish
Projmgmt-17/14
Step 4 - Calculate Initial Schedule
There are 3 major steps– Step 1 - Forward Pass - Determine the Early
Start (ES) and Early Finish (EF) for each task Works through tasks from start to finish
– Step 2 - Backward Pass - Determine the late start (LS) and late finish (LF) dates.
Works backward through tasks from end to start
– Step 3 - Calculate Float - Determine the schedule flexibility for each task.
Calculated by subtracting the ES from LS.
Projmgmt-18/14
Step 3 - Calculate Float
Float? - Some tasks have schedule flexibility
– others have none - E.g, those in the Critical Path– it is a measure of schedule flexibility of a task
Float = ES - LS - duration
Projmgmt-19/14
Step 4 - Calculate Initial Schedule
3 4d
5 8
12 15
FL=7
2 4D
1 4
1 4
FL=0
1 2D
1 2
10 11
FL=9
4 1d
9 9
16 16
FL=7
Start
5 1`2D
5 16
5 16
FL=0
Finish
FL=(16+1)-5-12FL=(4+1)-1-4
FL=(16+1)-9-1
FL=(11+1)-1-2 FL=(15+1)-5-4
Projmgmt-20/14
Time-Scaled View
Figure 7-5 page 136 shows a time scaled view of above diagram
– wider boxes show the task duration– float is shown indirectly
Figure 7.6 shows network diagram for entire home landscape project
Projmgmt-21/14
From Project Definition
Project
Rules
ScopeDeliverables
PrePlanningRisk Management
- Develop Approach- Risk Management
Step 1Develop a WBS
All
Project
TasksStep 2
Sequence thetasks
Step 3Estimate the
work packages
Duration
Estimates
Step 4:Calculate an
initialschedule
Equi
pmen
t
requ
irem
ents
& la
bor &
ski
ll
estim
ates
Step 5:Assign & level
resources
Cr i
tica
lP
ath
, f l
oat
,m
iles
ton
es
Step 6DevelopBudget
Realistic schedule& forecast
No
n-l
abo
rco
sts
Realistic schedule
& forecast
Project Plan- all project task s
- schedule- responsibilities
- budgetResource forecase
All
Pro
ject
Tas
ks
Net
wd
iag
ram
s
Projmgmt-22/14
Step 5: Assign & Level Resources
Goal: Optimize the use of resources– continuos use of fewest resources possible– avoid repeatedly adding a reusing resources– that is, limited people and resources affect the
schedule Figure 7.6 network diagram shows can build fence
and put in lawn at the same time.– Not take into consideration over allocation of teens– Figure 7.11 shows the resource shreadsheet.
Note teens heavily overallocated– Figure 7.13 shows same project with resources
leveled (3 teens @ 8 hrs per day with no more than 24 total hours per day).
Projmgmt-23/14
Step 5: Assign & Level Resources: The Process
Resources: People, equipment, and raw materials – Resource leveling - focus only on people and
equipment 4 steps to level resources
1. Forecast resources throughout project. Use resource spreadsheet such as figure 7.11 Creates an early start schedule - usually with
lots of uneconomical resource peaks and valleys (e.g., teen overallocation)
2. Identify resource peaks Use resource spreadsheet (figure 7.11) &
resource histogram (figure 7.12)
Projmgmt-24/14
Step 5: Assign & Level Resources: The Process (steps 3
& 4) 4 steps to level resources
1. Forecast resources throughout project.
2. Identify resource peaks
3. Delay non-critical tasks within their float. Use the float to fill in the resource valleys (I.e., spreading
resources out over time when schedule permits) See figure 7.13 compare to figure 7.12- task 5 was
delayed within float to balance resources.
4. Re-examine resource peaks - Look again at peaks, can redistribute schedule affecting
resource? Task 12 on 7.13 changed from 2 teens for 1 day to 1
teen for 3 days
Projmgmt-25/14
Step 5: Assign & Level Resources: Now what?
What happens if new schedule still unexceptable?
– The project date might now be pushed out longer than acceptable
You could accept the new date Work additional resources likely need to involve sponsor &/or
customer to make decision(s)