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Project Scheduling and Risk Management

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Previous Discussion

Function Point Cocomo Model Discussion

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The Four P’s

People — the most important element of a successful project

Product — the software to be built Process — the set of framework activities and

software engineering tasks to get the job done Project — all work required to make the

product a reality

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Stakeholders Senior managers who define the business issues that

often have significant influence on the project. Project (technical) managers who must plan, motivate,

organize, and control the practitioners who do software work.

Practitioners who deliver the technical skills that are necessary to engineer a product or application.

Customers who specify the requirements for the software to be engineered and other stakeholders who have a peripheral interest in the outcome.

End-users who interact with the software once it is released for production use.

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Software TeamsHow to lead?

How to organize?

How to motivate?

How to collaborate?

How to create good ideas?

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Team Leader The MOI Model

Motivation. The ability to encourage (by “push or pull”) technical people to produce to their best ability.

Organization. The ability to mold existing processes (or invent new ones) that will enable the initial concept to be translated into a final product.

Ideas or innovation. The ability to encourage people to create and feel creative even when they must work within bounds established for a particular software product or application.

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Software Teams

the difficulty of the problem to be solved the size of the resultant program(s) in lines of code or

function points the time that the team will stay together (team lifetime) the degree to which the problem can be modularized the required quality and reliability of the system to be

built the rigidity of the delivery date the degree of sociability (communication) required for

the project

The following factors must be considered when selecting a software project team structure ...

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closed paradigm—structures a team along a traditional hierarchy of authority

random paradigm—structures a team loosely and depends on individual initiative of the team members

open paradigm—attempts to structure a team in a manner that achieves some of the controls associated with the closed paradigm but also much of the innovation that occurs when using the random paradigm

synchronous paradigm—relies on the natural compartmentalization of a problem and organizes team members to work on pieces of the problem with little active communication among themselves

Organizational Paradigms

suggested by Constantine [Con93]

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Why Are Projects Late? an unrealistic deadline established by someone outside the

software development group changing customer requirements that are not reflected in

schedule changes; an honest underestimate of the amount of effort and/or the

number of resources that will be required to do the job; predictable and/or unpredictable risks that were not considered

when the project commenced; technical difficulties that could not have been foreseen in

advance; human difficulties that could not have been foreseen in advance; miscommunication among project staff that results in delays; a failure by project management to recognize that the project is

falling behind schedule and a lack of action to correct the problem

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Scheduling Principles compartmentalization—define distinct tasks interdependency—indicate task

interrelationship effort validation—be sure resources are

available defined responsibilities—people must be

assigned defined outcomes—each task must have an

output defined milestones—review for quality

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Effort Allocation

“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

40-50%

30-40%

15-20%

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Defining Task Sets

determine type of project assess the degree of rigor required identify adaptation criteria select appropriate software engineering tasks

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CPM Definition: In CPM activities are shown as a network of

precedence relationships using activity-on-node network construction

Single estimate of activity time Deterministic activity times

USED IN : Production management - for the jobs of repetitive in nature where the activity time estimates can be predicted with considerable certainty due to the existence of past experience.

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Critical Path Analysis

Activity duration

Shower 3

Dry hair 8

Fetch car 7

Iron clothes 12

Dress and make-up 10

Drive to interview 20

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Precedence table

Activity Immediately preceding activities

duration

A Shower - 3

B Dry hair A 8

C Fetch car - 7

D Iron clothes - 12

E Dress and make-up B,D 10

F Drive to interview C,E 20

The last activities that must be completed

before an activity can begin

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Activity on Arc Network

A(3)

D(12)

B(8)

E(10)

C(7) F(20)

1 5

4

3

2

The network will build up with each mouse click, in the order you would construct it on paper.

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Event Times

A(3)

D(12)

B(8)

E(10)

C(7) F(20)

1 5

4

3

2

Earliest event timeEET

Latest event timeLET

Each event node needs two boxes, to mark in the event times.

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Earliest Event Times

A(3)

D(12)

B(8)

E(10)

C(7) F(20)

1 5

4

3

2

0

3

12

22

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To find EETs, work forwards through the network from the start node to the finish node.

The EET for an event occurs when all activities leading into that event are complete.

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Latest Event Times

A(3)

D(12)

B(8)

E(10)

C(7) F(20)

1 5

4

3

23

0

12

22

42 42

22

12

4

0

To find LETs, work backwards through the network from the finish node to the start node.

The LET for an event is the latest it can occur without delaying subsequent events.

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Critical Activities

A(3)

D(12)

B(8)

E(10)

C(7) F(20)

1 5

4

3

23 4

0 0

12 12

22 22

42 42

Critical activities are activities that cannot run late. For critical activities:

Latest finish — Earliest start = length of activity

The green arrows mark the critical activities, which form the critical path. The critical path(s) must form a continuous route from the start node to the finish node.

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Timeline Charts

Tasks Week 1 Week 2 Week 3 Week 4 Week n

Task 1Task 2Task 3Task 4Task 5Task 6Task 7Task 8Task 9Task 10Task 11Task 12

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Use Automated Tools toDerive a Timeline Chart

I.1.1 Identify need and benefits Meet with customers Identify needs and project constraints Establish product statement Milestone: product statement definedI.1.2 Define desired output/control/input (OCI) Scope keyboard functions Scope voice input functions Scope modes of interaction Scope document diagnostics Scope other WP functions Document OCI FTR: Review OCI with customer Revise OCI as required; Milestone; OCI definedI.1.3 Define the functionality/behavior Define keyboard functions Define voice input functions Decribe modes of interaction Decribe spell/grammar check Decribe other WP functions FTR: Review OCI definition with customer Revise as required Milestone: OCI defintition completeI.1.4 Isolate software elements Milestone: Software elements definedI.1.5 Research availability of existing software Reseach text editiong components Research voice input components Research file management components Research Spell/Grammar check components Milestone: Reusable components identifiedI.1.6 Define technical feasibility Evaluate voice input Evaluate grammar checking Milestone: Technical feasibility assessedI.1.7 Make quick estimate of sizeI.1.8 Create a Scope Definition Review scope document with customer Revise document as required Milestone: Scope document complete

week 1 week 2 week 3 week 4Work tasks week 5

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Schedule Tracking conduct periodic project status meetings in which

each team member reports progress and problems. evaluate the results of all reviews conducted

throughout the software engineering process. determine whether formal project milestones (the

diamonds shown in Figure 27.3) have been accomplished by the scheduled date.

compare actual start-date to planned start-date for each project task listed in the resource table (Figure 27.4).

meet informally with practitioners to obtain their subjective assessment of progress to date and problems on the horizon.

use earned value analysis (Section 27.6) to assess progress quantitatively.

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Earned Value Analysis (EVA) Earned value

is a measure of progress enables us to assess the “percent of completeness”

of a project using quantitative analysis rather than rely on a gut feeling

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Computing Earned Value-I The budgeted cost of work scheduled (BCWS) is

determined for each work task represented in the schedule. BCWSi is the effort planned for work task i. To determine progress at a given point along the project

schedule, the value of BCWS is the sum of the BCWSi values for all work tasks that should have been completed by that point in time on the project schedule.

The BCWS values for all work tasks are summed to derive the budget at completion, BAC. Hence,

BAC = ∑ (BCWSk) for all tasks k

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Computing Earned Value-II Next, the value for budgeted cost of work performed

(BCWP) is computed. The value for BCWP is the sum of the BCWS values for all

work tasks that have actually been completed by a point in time on the project schedule.

“the distinction between the BCWS and the BCWP is that the former represents the budget of the activities that were planned to be completed and the latter represents the budget of the activities that actually were completed.” [Wil99]

Given values for BCWS, BAC, and BCWP, important progress indicators can be computed:

• Schedule performance index, SPI = BCWP/BCWS• Schedule variance, SV = BCWP – BCWS• SPI is an indication of the efficiency with which the project is

utilizing scheduled resources.

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Computing Earned Value-III Percent scheduled for completion = BCWS/BAC

provides an indication of the percentage of work that should have been completed by time t.

Percent complete = BCWP/BAC provides a quantitative indication of the percent of completeness of

the project at a given point in time, t. Actual cost of work performed, ACWP, is the sum of the effort

actually expended on work tasks that have been completed by a point in time on the project schedule. It is then possible to compute

• Cost performance index, CPI = BCWP/ACWP• Cost variance, CV = BCWP – ACWP

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Project Risks

What can go wrong?What is the likelihood?What will the damage be?What can we do about it?

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Reactive Risk Management

project team reacts to risks when they occur

mitigation—plan for additional resources in anticipation of fire fighting

fix on failure—resource are found and applied when the risk strikes

crisis management—failure does not respond to applied resources and project is in jeopardy

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Proactive Risk Management

formal risk analysis is performed organization corrects the root causes of risk

TQM concepts and statistical SQA examining risk sources that lie beyond the

bounds of the software developing the skill to manage change

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RISK

Risk Management Paradigm

control

identify

analyze

plan

track

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Risk Identification Product size—risks associated with the overall size of the software to be

built or modified. Business impact—risks associated with constraints imposed by

management or the marketplace. Customer characteristics—risks associated with the sophistication of the

customer and the developer's ability to communicate with the customer in a timely manner.

Process definition—risks associated with the degree to which the software process has been defined and is followed by the development organization.

Development environment—risks associated with the availability and quality of the tools to be used to build the product.

Technology to be built—risks associated with the complexity of the system to be built and the "newness" of the technology that is packaged by the system.

Staff size and experience—risks associated with the overall technical and project experience of the software engineers who will do the work.

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Risk Components performance risk—the degree of uncertainty

that the product will meet its requirements and be fit for its intended use.

cost risk—the degree of uncertainty that the project budget will be maintained.

support risk—the degree of uncertainty that the resultant software will be easy to correct, adapt, and enhance.

schedule risk—the degree of uncertainty that the project schedule will be maintained and that the product will be delivered on time.

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Risk Projection Risk projection, also called risk estimation,

attempts to rate each risk in two ways the likelihood or probability that the risk is real the consequences of the problems associated with

the risk, should it occur. The are four risk projection steps:

establish a scale that reflects the perceived likelihood of a risk

delineate the consequences of the risk estimate the impact of the risk on the project and the

product, note the overall accuracy of the risk projection so

that there will be no misunderstandings.

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Building a Risk Table

Risk Probability Impact RMMM

RiskMitigationMonitoring

& Management

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Building the Risk Table

Estimate the probability of occurrence Estimate the impact on the project on a

scale of 1 to 5, where 1 = low impact on project success 5 = catastrophic impact on project success

sort the table by probability and impact

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Risk Exposure (Impact)

The overall risk exposure, RE, is determined using the following relationship [Hal98]:

RE = P x C

where P is the probability of occurrence for a risk, and C is the cost to the project should the risk occur.

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Risk Exposure Example Risk identification. Only 70 percent of the software

components scheduled for reuse will, in fact, be integrated into the application. The remaining functionality will have to be custom developed.

Risk probability. 80% (likely). Risk impact. 60 reusable software components were planned.

If only 70 percent can be used, 18 components would have to be developed from scratch (in addition to other custom software that has been scheduled for development). Since the average component is 100 LOC and local data indicate that the software engineering cost for each LOC is $14.00, the overall cost (impact) to develop the components would be 18 x 100 x 14 = $25,200.

Risk exposure. RE = 0.80 x 25,200 ~ $20,200.

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mitigation—how can we avoid the risk? monitoring—what factors can we track that

will enable us to determine if the risk is becoming more or less likely?

management—what contingency plans do we have if the risk becomes a reality?

Risk Mitigation, Monitoring,and Management

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Risk Due to Product Size

• estimated size of the product in LOC or FP?

• estimated size of product in number of programs, files, transactions?

• percentage deviation in size of product from average for previous products?

• size of database created or used by the product?

• number of users of the product?

• number of projected changes to the requirements for the product? before delivery? after delivery?

• amount of reused software?

Attributes that affect risk:

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Risk Due to Business Impact

• affect of this product on company revenue?

• visibility of this product by senior management?

• reasonableness of delivery deadline?

• number of customers who will use this product

• interoperability constraints

• sophistication of end users?

• amount and quality of product documentation that must be produced and delivered to the customer?

• governmental constraints

• costs associated with late delivery?

• costs associated with a defective product?

Attributes that affect risk:

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Risks Due to the Customer

• Have you worked with the customer in the past?

• Does the customer have a solid idea of requirements?

• Has the customer agreed to spend time with you?

• Is the customer willing to participate in reviews?

• Is the customer technically sophisticated?

• Is the customer willing to let your people do their job—that is, will the customer resist looking over your shoulder during technically detailed work?

• Does the customer understand the software

engineering process?

Questions that must be answered:

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Risks Due to Process Maturity

• Have you established a common process framework?

• Is it followed by project teams?

• Do you have management support for software engineering

• Do you have a proactive approach to SQA?

• Do you conduct formal technical reviews?

• Are CASE tools used for analysis, design and testing?

• Are the tools integrated with one another?

• Have document formats been established?

Questions that must be answered: