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COMP442 Project ManagementCOMP442 Project Management

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Session ObjectivesSession Objectives

Planning & scheduling Work Breakdown Structure Realistic Estimating Critical Path

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Project Time Management ProcessesProject Time Management Processes

Project time management involves processes required to ensure timely completion of a project

Processes include: Activity definition Activity sequencing Activity duration estimating Schedule development Schedule control

Estimating: Work Breakdown StructureEstimating: Work Breakdown Structure “Project best understood by breaking it down

into its parts” Work Breakdown Structure (WBS)

powerful tool for doing this (not just a task list) defines the total scope of the project fundamental to much of project planning & tracking

Start at top, progressively break work down (tree structure) into work packages

Roll up the packages for bottom up estimating Packages give clear work assignments

Sample Intranet WBS Sample Intranet WBS Organized by PhaseOrganized by Phase

Intranet WBS in Tabular FormIntranet WBS in Tabular Form1.0 Concept

1.1 Evaluate current systems1.2 Define Requirements

1.2.1 Define user requirements1.2.2 Define content requirements1.2.3 Define system requirements1.2.4 Define server owner requirements

1.3 Define specific functionality1.4 Define risks and risk management approach1.5 Develop project plan1.6 Brief web development team

2.0 Web Site Design3.0 Web Site Development4.0 Roll Out5.0 Support

Intranet WBS and Gantt ChartIntranet WBS and Gantt Chart

Project 98 file

Intranet WBS & Gantt Chart Organized by PM GroupsIntranet WBS & Gantt Chart Organized by PM Groups

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Realistic Estimating (Frame)Realistic Estimating (Frame)

Lots of reasons for poor estimates inexperience, technical problems, changes

optimists, low-balling, politics

Bottom-up cost estimating rollup the WBS packages

Top-down or Parametric estimating from experience to complex models

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Realistic Estimating (cont.)Realistic Estimating (cont.)

Which technique is better? ideally use both early on don’t have WBS so must use

top-down accuracy of top-down depends on

availability/quality of historical data building complete WBS can be

expensive, but guesses can be even more costly

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Work Package (Marchewka)Work Package (Marchewka)

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Deliverables and MilestonesDeliverables and Milestones Deliverables

Tangible, verifiable work products Reports, presentations, prototypes, etc.

Milestones Significant events or achievements Acceptance of deliverables or phase

completion Cruxes (proof of concepts) Quality control Keeps team focused

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Developing the WBSDeveloping the WBS

Develop work packages for each of the phases and deliverables defined in the Deliverable Structure Chart (DSC)

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Work Breakdown ScheduleWork Breakdown Schedule

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Software Engineering MetricsSoftware Engineering Metrics

Lines of Code (LOC)Function Points

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Lines of Code (LOC)Lines of Code (LOC)

Most traditionally used metric for project sizing

Most controversial Count comments? Declaring variables? Efficient code vs. code bloat Language differences Easier to count afterwards than to estimate

The Application Boundary for The Application Boundary for Function Point AnalysisFunction Point Analysis

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The Mythical Man-Month – Frederick BrooksThe Mythical Man-Month – Frederick Brooks

1. 0ur techniques of estimation are poorly developed.More seriously, they reflect an unvoiced assumption which is quite untrue i.e., that all will go well.

2. Our estimating techniques fallaciously confuse effort with progress, hiding the assumption that men and months are interchangeable.

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The Mythical Man-Month – Frederick BrooksThe Mythical Man-Month – Frederick Brooks

3. Because we are uncertain of our estimates,software managers often lack the courteous stubbornness of Antoines chef

4. Schedule progress is poorly monitored.Techniques proven and routine in other engineering disciplines are considered radical innovations in software engineering

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The Mythical Man-Month – Frederick BrooksThe Mythical Man-Month – Frederick Brooks

5. When schedule slippage is recognized, the natural tendency (and traditional) response it to add more manpower. Like dousing a fire with gasoline,this makes matters worse, much worse. More fire requires more gasoline, and thus begins a regenerative cycle which ends in disaster.

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Brooks Law:

“Adding manpower to a late software project makes it

later.”

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Scheduling Tools & MethodsScheduling Tools & Methods

Gantt ChartsCritical Path Method (CPM)Program Evaluation and Review

Technique (PERT)

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The Project Planning FrameworkThe Project Planning Framework

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Developing a Project ScheduleDeveloping a Project Schedule

Base documents Project charter

– start/end dates (tentative), budget Scope statement

– what will be done (& not done)

Activity definitions develop detailed WBS plus supporting explanations to understand

all work to be done

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Activity SequencingActivity Sequencing Review activities & determine

dependencies Mandatory dependencies: inherent in the

nature of the work; hard logic Discretionary: defined by the project team;

soft logic External: involve relationships between

project and external activities Must Must determine dependencies to use

critical path analysis

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Gantt ChartsGantt Charts Created 1800 Standard format for displaying

project schedules activities, durations, start/end finish

dates displayed in calendar format Advantages

enforces planning easy to create & understand preferred for summary/exec-level

information

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Gantt Charts (cont.)Gantt Charts (cont.)

Symbols include: black diamond: milestones Thick black bars: summary tasks Lighter horizontal bars: tasks Arrows: dependencies between tasks

Bar Charts Simplified version Serve similar function

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Sample Project Gantt ChartSample Project Gantt Chart

Sample Tracking Gantt ChartSample Tracking Gantt Chart

white diamond: slipped milestone

two bars: planned and actual times

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Critical Path Method (CPM)Critical Path Method (CPM) Developed 1957 CPM diagram shows activities,

durations, start/end dates & sequencesequence in which they must be completed

Critical path for project is the series of activities that determines the earliest earliest timetime by which project can be completed

Critical path is longest pathlongest path through network diagram, has least (zero) slack or float

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CPM (cont.)CPM (cont.)

Critical path helps you make schedule trade-offs

Slack or floatSlack or float amount of time activity can be delayed without delaying early start of dependent activities

Simple Example of Determining Critical PathSimple Example of Determining Critical Path consider following network diagram assume all times in days

2 3

4

5

A=2 B=5C=2

D=7

1 6

F=2

E=1

start finish

a. How many paths are on this network diagram?

b. How long is each path?

c. Which is the critical path?

d. What is the shortest amount of time needed to complete this project?

Activity-on-Arrow (AOA) Network Diagram

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Precedence Diagramming Method (PDM)Precedence Diagramming Method (PDM)

Activities are represented by boxes Arrows show relationships between

activities More popular than ADM method as

used by PM software Better at showing different types of

dependencies

Task Dependency TypesTask Dependency Types

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Activity Analysis for AONActivity Analysis for AON

Activity Description Estimated Duration (Days)

Predecessor

A Evaluate current technology platform

2 None

B Define user requirements 5 A

C Design Web page layouts 4 B

D Set-up Server 3 B

E Estimate Web traffic 1 B

F Test Web pages and links 4 C,D

G Move web pages to production environment

3 D,E

H Write announcement of intranet for corp. newsletter

2 F,G

I Train users 5 G

J Write report to management 1 H,I

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Possible Activity PathsPossible Activity PathsPossible Paths Path Total

Path 1 A+B+C+F+H+J 18

2+5+4+4+2+1

Path 2 A+B+D+F+H+J 17

2+5+3+4+2+1

Path 3 A+B+D+G+H+J 16

2+5+3+3+2+1

Path 4 A+B+D+G+I+J 19*

2+5+3+3+5+1

Path 5 A+B+E+G+I+J 17

2+5+1+3+5+1

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Critical PathCritical Path Longest path Shortest time project can be completed

Zero slack (or float)The amount of time an activity can be delayed

before it delays the project Must be monitored and managed!

PM can expedite or crash Can fast track The CP can change Can have multiple CPs

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Techniques for Shortening a Project ScheduleTechniques for Shortening a Project Schedule

Shortening durations of critical tasks: add more resources change their scope

Crashing tasks by obtaining the greatest amount of schedule compression for the least incremental cost

Fast tracking tasks by doing them in parallel or overlapping them

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PERTPERT

Developed 1959 for Polaris project Similar to CPM but addresses

uncertainties in task durations Uses probabilistic time estimates –

optimistic, most likely, pessimistic estimates of activity durations

PERT Formula and ExamplePERT Formula and Example

PERT weighted average formula: optimistic time + 4X most likely time + pessimistic time

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Example:

PERT weighted average =

8 workdays + 4 X 10 workdays + 24 workdays = 12 days

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where 8 = optimistic time, 10 = most likely time, and 24 = pessimistic time

Activity Analysis for PERTActivity Analysis for PERTActivity Predecessor Optimistic

Estimates (Days)

Most Likely Estimates

(Days)

Pessimistic Estimates

(Days)

Expected Duration

(a+4b+c)

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A None 1 2 4 2.2

B A 3 5 8 5.2

C B 2 4 5 3.8

D B 2 3 6 3.3

E B 1 1 1 1.0

F C,D 2 4 6 4.0

G D,E 2 3 4 3.0

H F,G 1 2 5 2.3

I G 4 5 9 5.5

J H,I .5 1 3 1.3

30 days 31.6 days

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Selecting Scheduling ApproachSelecting Scheduling Approach Consider project size, risk and

complexity Gantt

senior management smaller, less complex projects

CPM medium size/complexity/risk

PERT high risk projects medium to high complexity

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