Project Scheduling & Project Scheduling & TrackingTracking

Why Software Is Delivered Late?Why Software Is Delivered Late?

• An unrealistic deadline • Changing but unpredicted customer requirements• Underestimation of efforts needed• Risks not considered at the project start• Unforeseen technical difficulties• Unforeseen human difficulties• Miscommunication among project staff• Failure to recognize that project is falling behind

schedule

““One day a time”One day a time”

All technical projects involve 100s of small tasksSome tasks do no affect the project completionOther tasks are criticalcritical for project completionProject manager must:

define all project tasks build a network that depicts their interdependence identify the critical tasks track the progress of these tasks recognize the delay “one day at a time”one day at a time”

Two different Perspectives to Two different Perspectives to view Schedulingview Scheduling

End date for completion has been finalized

End date for completion has been finalized

Only Rough time-frame is

given

Only Rough time-frame is

given

Basic Principles for SE SchedulingBasic Principles for SE Scheduling

• Compartmentalization – Compartmentalization – define distinct tasksdefine distinct tasks

• Interdependency- Interdependency- parallel and sequential tasksparallel and sequential tasks

• Time allocation - Time allocation - assigned person days, start time, assigned person days, start time,

ending timeending time))• Effort validation - Effort validation - be sure resources are available

• Defined responsibilities Defined responsibilities — people must be assigned

• Defined Outcomes- Defined Outcomes- each task must have an outputeach task must have an output

• Defined milestones - Defined milestones - review for qualityreview for quality

People and EffortPeople and Effort

“If we fall behind schedule we can always add more programmersand catch uo late in the project”

“If we fall behind schedule we can always add more programmersand catch uo late in the project”

Has a disruptive effect on the project

Schedules slip even further

People and EffortPeople and Effort

The relationship between the number of people working in software project and

overall productivity is not linear

The relationship between the number of people working in software project and

overall productivity is not linear

Fewer people and longer time period is a better option for software

development

Fewer people and longer time period is a better option for software

development

Effort DistributionEffort Distribution

Front-end Analysis &

Design

40-20-4040-20-40

Back-end testing

Coding

Effort Allocation

40-50%40-50%

30-40%30-40%

• “front end” activities– customer communication– analysis– design– review and modification

• construction activities– coding or code generation

• testing and installation– unit, integration– white-box, black box– regression

15-20%15-20%

Effort DistributionEffort Distribution

RA

SD

Coding

PI

Testing

(2-3%)

(20-25%)

(15 -20%)

(20-25%)

(30 - 40%)

Defining Task Sets

• determine type of project• assess the degree of rigor required

– identify adaptation criteria– compute task set selector (TSS) value– interpret TSS to determine degree of rigor

• select appropriate software engineering tasks

Software Project TypesSoftware Project Types

• Concept Development projects Concept Development projects

• New Application Development Projects New Application Development Projects

• Application Enhancement ProjectApplication Enhancement Project

• Application Maintenance ProjectApplication Maintenance Project

• Reengineering ProjectReengineering Project

Degree of RigorDegree of RigorCasualCasual• Minimum task set is required•Umbrella tasks are minimized•Documentation requirements are reduced•Basic principles of SE are applicable

CasualCasual• Minimum task set is required•Umbrella tasks are minimized•Documentation requirements are reduced•Basic principles of SE are applicable

StructuredStructured•Framework activities will be applied•Umbrella tasks are applied•Documentation and measurement tasks will be done in a streamlines manner

StructuredStructured•Framework activities will be applied•Umbrella tasks are applied•Documentation and measurement tasks will be done in a streamlines manner

StrictStrict•Full process will be applied•Degree of discipline ensures high quality•All umbrella activities will be applied•Robust work products will be produced

StrictStrict•Full process will be applied•Degree of discipline ensures high quality•All umbrella activities will be applied•Robust work products will be produced

Quick ReactionQuick Reaction•Process framework will be applied•Only essential tasks will be undertaken• Documentation will be provided after product delivery

Quick ReactionQuick Reaction•Process framework will be applied•Only essential tasks will be undertaken• Documentation will be provided after product delivery

Adaptation CriteriaAdaptation Criteria

• Size of the ProjectSize of the Project• Number of potential usersNumber of potential users• Mission criticalityMission criticality• Application Longevity Application Longevity • Stability requirementsStability requirements• Ease of communicationEase of communication• Maturity of technologyMaturity of technology• Performance constraintsPerformance constraints• Embedded and non-embedded characteristicsEmbedded and non-embedded characteristics• Project staffProject staff• Reengineering factorsReengineering factors

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Task Set selectorTask Set selector• Based on adaptation criteria, TSS is computedBased on adaptation criteria, TSS is computed

TSS > 1.2

StrictStrict

1.0 < TSS < 3.0

CasualCasual

TSS > 2.4

StructuredStructured

Defining a task NetworkDefining a task Network• Task Network is a graphic representation of the

task flow for the project.• It shows all the SE tasks• First it is created at a macroscopic level• Tasks on the critical path (chain of tasks

determining the duration of the project) are marked• Size of the Project

Figure 7.2 Concept development tasks using anevolutionary model

Project Definition

I.1 Concept scoping

Concept Development

New ApplicationDevelopmentApplication

EnhancementApplicationMaintenance

I.4 Proof of concept

I.5 Concept implementation

Planning

ReleaseCustomerEvaluation

Engineering/Construction

I.6 Customer reaction

I.2 Preliminary concept planningI.3 Technology risk assessment

Reengineering

Project SchedulingProject Scheduling

Program Evaluation and Review Technique

(PERT)

Critical Path

Method (CPM)

I.1Conceptscoping

I.3aTech. Risk

Assessment

I.3bTech. Risk

Assessment

I.3cTech. Risk

Assessment

Three I.3 tasks areapplied in parallel to3 different conceptfunctions

Three I.3 tasks areapplied in parallel to3 different conceptfunctions

I.4Proof ofConcept

I.5aConcept

Implement.

I.5bConcept

Implement.

I.5cConcept

Implement.

I.2Conceptplanning

I.6CustomerReaction

Integratea, b, c

Project SchedulingProject Scheduling

Both techniques (PERT and CPM) are driven by information already developed in earlier project planning activities:– Estimates of efforts– Decomposition of product function– selection of appropriate process model and

task set– Decomposition of tasks

Project SchedulingProject Scheduling

• Both PERT and CPM provides Both PERT and CPM provides quantitative quantitative tools totools to

– determine the critical pathdetermine the critical path

– establish the most likely time estimated for establish the most likely time estimated for individual tasks by applying statistical individual tasks by applying statistical modelsmodels

– calculate boundary time (window) for a calculate boundary time (window) for a particular taskparticular task

Project SchedulingProject SchedulingImportant boundary times for PERT and CPMImportant boundary times for PERT and CPM

Earliest timeEarliest time a task can begin when all preceding tasks are completed in shores possible time

Latest timeLatest time for task initiation before the minimum project completion time is delayed

Earliest finish Earliest finish -- the sum of the earliest start and the task duration

Latest Latest finishfinish - the latest start time added to task duration

TTotal floatotal float - the amount of surplus time allowed in scheduling tasks so that the network critical path is maintained on schedule

Timeline/Gantt Chart

Jan Feb Mar Apr May June

Pro

ject

Act

ivit

ies

Milestone

Project TableWorkTasks

PlannedStart

ActualStart

PlannedComplete

ActualComplete

PersonAssigned

EffortNeeded

Notes

Tracking the Project ScheduleTracking the Project Schedule• It is a road map for the Software Project

• It defines the tasks and milestones

• Tracking can be done by:

– Conducting periodic project status meetings

– Evaluating the results of all reviews

– Determining whether milestones were reached by the scheduled date

– Compare actual start date to planned start date

– Meeting informally with professionals to get their subjective opinion

– Using earned value analysis

Tracking the Project ScheduleTracking the Project ScheduleAdminister

Project Resources

Cope with problems

Direct Project

staff

Control

Tracking the Project ScheduleTracking the Project Schedule

Project is on schedule and within budget

Problem diagnosed

Additional resources focussed on problem area

Additional resources focussed on problem area

Project Tracking

Staff may be redeployedStaff may be redeployed

Project Schedule can be redefinedProject Schedule can be redefined