Chapter 4.1

Software Project Planning

1

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

2

Product Process Project People

The People: The Stakeholders• Five categories of 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. 3

Software Teams

4

How to lead?

How to organize?

How to motivate?

How to collaborate?

How to create good ideas?

The People: Team Leaders• Qualities to look for in a team leader

– 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.

5

The People: The Software Team• Seven project factors to consider when structuring a software

development team– 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

project6

The Product Scope• Scope

• Context. How does the software to be built fit into a larger system, product, or business context and what constraints are imposed as a result of the context?

• Information objectives. What customer-visible data objects are produced as output from the software? What data objects are required for input?

• Function and performance. What function does the software perform to transform input data into output? Are any special performance characteristics to be addressed?

• Software project scope must be unambiguous and understandable at the management and technical levels.

7

Problem Decomposition• Sometimes called partitioning or problem

elaboration• Once scope is defined …

– It is decomposed into constituent functions– It is decomposed into user-visible data objectsor– It is decomposed into a set of problem classes

• Decomposition process continues until all functions or problem classes have been defined

8

The Process• Once a process framework has been established

– Consider project characteristics– Determine the degree of rigor required– Define a task set for each software engineering activity

• Task set =– Software engineering tasks– Work products– Quality assurance points– Milestones

9

The Project• Projects get into trouble when …

– Software people don’t understand their customer’s needs.– The product scope is poorly defined.– Changes are managed poorly.– The chosen technology changes.– Business needs change [or are ill-defined]. – Deadlines are unrealistic.– Users are resistant.– Sponsorship is lost [or was never properly obtained].– The project team lacks people with appropriate skills.– Managers [and practitioners] avoid best practices and lessons learned.

10

To Get to the Essence of a Project• Why is the system being developed?• What will be done? • When will it be accomplished?• Who is responsible?• Where are they organizationally located?• How will the job be done technically and managerially?• How much of each resource (e.g., people, software, tools,

database) will be needed?

11

Chapter 4.2

Process and Project Metrics

12

A Good Manager Measures

13

measurement

What do weuse as abasis? • size? • function?

project metrics

process metricsprocess

product

product metrics

Why Do We Measure?• assess the status of an ongoing project• track potential risks• uncover problem areas before they go “critical,”• adjust work flow or tasks, • evaluate the project team’s ability to control quality of

software work products.

14

Process Metrics• Quality-related

– focus on quality of work products and deliverables• Productivity-related

– Production of work-products related to effort expended• Statistical SQA data

– error categorization & analysis• Defect removal efficiency

– propagation of errors from process activity to activity• Reuse data

– The number of components produced and their degree of reusability

15

Typical Project Metrics• Effort/time per software engineering task• Errors uncovered per review hour• Scheduled vs. actual milestone dates• Changes (number) and their characteristics• Distribution of effort on software engineering tasks

16

Typical Size-Oriented Metrics• errors per KLOC (thousand lines of code)• defects per KLOC• $ per LOC• pages of documentation per KLOC• errors per person-month• errors per review hour• LOC per person-month• $ per page of documentation

17

Typical Function-Oriented Metrics

• errors per FP (thousand lines of code)• defects per FP• $ per FP• pages of documentation per FP• FP per person-month

18

Function-Oriented Metrics• FP are computed by

FP = count-total * [0.65 + 0.01 * Sum(Fi)]• count-total is the sum of all FP entries• The Fi (i = 1 to 14) are "complexity adjustment values" based on

responses to the following questions [ART85]:1. Does the system require reliable backup and recovery?2. Are data communications required?3. Are there distributed processing functions?4. Is performance critical?...

• Each of these questions is answered using a scale that ranges from 0 (not important or applicable) to 5 (absolutely essential). 19

Comparing LOC and FP

20

Programming LOC per Function point

Language avg. median low high

Ada 154 - 104 205Assembler 337 315 91 694C 162 109 33 704C++ 66 53 29 178

COBOL 77 77 14 400Java 63 53 77 -JavaScript 58 63 42 75Perl 60 - - -PL/1 78 67 22 263Powerbuilder 32 31 11 105SAS 40 41 33 49Smalltalk 26 19 10 55SQL 40 37 7 110Visual Basic 47 42 16 158

Representative values developed by QSM

Object-Oriented Metrics• Number of scenario scripts (use-cases)• Number of support classes (required to implement

the system but are not immediately related to the problem domain)

• Average number of support classes per key class (analysis class)

• Number of subsystems (an aggregation of classes that support a function that is visible to the end-user of a system)

21

WebApp Project Metrics• Number of static Web pages (the end-user has no control over the

content displayed on the page)• Number of dynamic Web pages (end-user actions result in customized

content displayed on the page)• Number of internal page links (internal page links are pointers that

provide a hyperlink to some other Web page within the WebApp)• Number of persistent data objects• Number of external systems interfaced• Number of static content objects• Number of dynamic content objects• Number of executable functions

22

Measuring Quality• Correctness — the degree to which a program

operates according to specification• Maintainability—the degree to which a program is

amenable to change• Integrity—the degree to which a program is

impervious to outside attack• Usability—the degree to which a program is easy to

use

23

Defect Removal Efficiency

24

where:E is the number of errors found before delivery of the software to the end-user D is the number of defects found after delivery.

DRE = E /(E + D)

Chapter 4.3

Estimation for Software Projects

25

Software Project Planning

26

The overall goal of project planning is to establish a pragmatic strategy for controlling, tracking, and monitoring a complex technical project.

Why?

So the end result gets done on time, with quality!

Project Planning Task Set-I

• Establish project scope• Determine feasibility• Analyze risks• Define required resources

– Determine required human resources– Define reusable software resources– Identify environmental resources

27

Project Planning Task Set-II• Estimate cost and effort

– Decompose the problem– Develop two or more estimates using size, function points,

process tasks or use-cases– Reconcile the estimates

• Develop a project schedule– Establish a meaningful task set– Define a task network– Use scheduling tools to develop a timeline chart– Define schedule tracking mechanisms

28

Estimation

• Estimation of resources, cost, and schedule for a software engineering effort requires – experience– access to good historical information (metrics)– the courage to commit to quantitative predictions

when qualitative information is all that exists• Estimation carries inherent risk and this risk

leads to uncertainty

29

Write it Down!

30

SoftwareProject

Plan

Project ScopeEstimatesRisksScheduleControl strategy

What is Scope?• Software scope describes

– the functions and features that are to be delivered to end-users– the data that are input and output– the “content” that is presented to users as a consequence of

using the software– the performance, constraints, interfaces, and reliability that

bound the system. • Scope is defined using one of two techniques:

– A narrative description of software scope is developed after communication with all stakeholders.

– A set of use-cases is developed by end-users.31

Resource Estimation• Three major categories of software engineering resources

– People– Development environment– Reusable software components

• Often neglected during planning but become a paramount concern during the construction phase of the software process

• Each resource is specified with– A description of the resource– A statement of availability– The time when the resource will be required– The duration of time that the resource will be applied

32

Time window

Categories of Resources

33

People- Number required- Skills required- Geographical location

Development Environment- Software tools- Computer hardware- Network resources

Reusable Software Components- Off-the-shelf components- Full-experience components- Partial-experience components- New components

The Project

Human Resources• Planners need to select the number and the kind of people

skills needed to complete the project• They need to specify the organizational position and job

specialty for each person• Small projects of a few person-months may only need one

individual• Large projects spanning many person-months or years require

the location of the person to be specified also• The number of people required can be determined only after

an estimate of the development effort

34

Development Environment Resources

• A software engineering environment (SEE) incorporates hardware, software, and network resources that provide platforms and tools to develop and test software work products

• Most software organizations have many projects that require access to the SEE provided by the organization

• Planners must identify the time window required for hardware and software and verify that these resources will be available

35

Reusable Software Resources• Off-the-shelf components

– Components are from a third party or were developed for a previous project

– Ready to use; fully validated and documented; virtually no risk• Full-experience components

– Components are similar to the software that needs to be built– Software team has full experience in the application area of

these components– Modification of components will incur relatively low risk

36

Reusable Software Resources• Partial-experience components

– Components are related somehow to the software that needs to be built but will require substantial modification

– Software team has only limited experience in the application area of these components

– Modifications that are required have a fair degree of risk• New components

– Components must be built from scratch by the software team specifically for the needs of the current project

– Software team has no practical experience in the application area

– Software development of components has a high degree of risk37

Estimation Techniques

38

• Past (similar) project experience• Conventional estimation techniques

– task breakdown and effort estimates– size (e.g., FP) estimates

• Empirical models• Automated tools

Functional Decomposition

39

functional decomposition

Statementof

Scope Perform a Grammatical “parse”

Problem-Based Estimation• Start with a bounded statement of scope• Decompose the software into problem functions that can

each be estimated individually • Compute an LOC or FP value for each function• Derive cost or effort estimates by applying the LOC or FP

values to your baseline productivity metrics (e.g., LOC/person-month or FP/person-month)

• Combine function estimates to produce an overall estimate for the entire project

40

Problem-Based Estimation• In general, the LOC/pm and FP/pm metrics should be

computed by project domain– Important factors are team size, application area, and

complexity • LOC and FP estimation differ in the level of detail required for

decomposition with each value– For LOC, decomposition of functions is essential and should go

into considerable detail (the more detail, the more accurate the estimate)

– For FP, decomposition occurs for the five information domain characteristics and the 14 adjustment factors

• External inputs, external outputs, external inquiries, internal logical files, external interface files

41

Problem-Based Estimation• For both approaches, the planner uses lessons learned to

estimate an optimistic, most likely, and pessimistic size value for each function or count (for each information domain value)

• Then the expected size value S is computed as follows:

S = (Sopt + 4Sm + Spess)/6

• Historical LOC or FP data is then compared to S in order to cross-check it

42

Example: LOC Approach

43

Average productivity for systems of this type = 620 LOC/pm.

Burdened labor rate =$8000 per month, the cost per line of code is approximately $13.

Based on the LOC estimate and the historical productivity data, the total estimated project cost is $431,000 and the estimated effort is 54 person-months.

Example: FP Approach

44

The estimated number of FP is derived:FPestimated = count-total * [0.65 + 0.01 * Sum(Fi)] (see next)

FPestimated = 375

organizational average productivity = 6.5 FP/pm. burdened labor rate = $8000 per month, the cost per FP is approximately $1230. Based on the FP estimate and the historical productivity data, the total estimated project cost is $461,000 and the estimated effort is 58 person-months.

Complexity Adjustment FactorFactor Value

• Backup and recovery 4• Data communications 2• Distributed processing 0• Performance critical 4• Existing operating environment 3• On-line data entry 4• Input transaction over multiple screens 5• Master files updated on-line 3• Information domain values complex 5• Internal processing complex 5• Code designed for reuse 4• Conversion/installation in design 3• Multiple installations 5• Application designed for change 5 45

• Answer the factors using a scale that ranges from 0 (not important or applicable) to 5 (absolutely essential)

• Sum(Fi)=52

Example: FP Approach

46

The estimated number of FP is derived:FPestimated = count-total * [0.65 + 0.01 * Sum(Fi)]

FPestimated = 375

organizational average productivity = 6.5 FP/pm. burdened labor rate = $8000 per month, the cost per FP is approximately $1230. Based on the FP estimate and the historical productivity data, the total estimated project cost is $461,000 and the estimated effort is 58 person-months.

Process-Based Estimation• Identify the set of functions that the software needs to

perform as obtained from the project scope• Identify the series of framework activities that need to be

performed for each function• Estimate the effort (in person months) that will be required

to accomplish each software process activity for each function

47

Process-Based Estimation• Apply average labor rates (i.e., cost/unit effort) to the effort

estimated for each process activity• Compute the total cost and effort for each function and

each framework activity (See table in Pressman, p. 655)• Compare the resulting values to those obtained by way of

the LOC and FP estimates– If both sets of estimates agree, then your numbers are highly

reliable– Otherwise, conduct further investigation and analysis

concerning the function and activity breakdown

48

This is the most commonly used of the two estimation techniques (problem and process)

Process-Based Estimation

49

Obtained from “process framework”

applicationfunctions

framework activities

Effort required to accomplisheach framework activity for each application function

Process-Based Estimation Example

50

Activity

Task

Function

UICF2DGA3DGA

DSMPCF

CGDF

DAM

Totals

% effort

CC PlanningRisk

Analysis EngineeringConstruction

Release TotalsCE

analysis design code test

0.25 0.25 0.25 3.50 20.50 4.50 16.50 46.00

1% 1% 1% 8% 45% 10% 36%

CC = customer communication CE = customer evaluation

0.50

0.750.500.50

0.500.25

2.50

4.004.003.00

3.002.00

0.40

0.601.001.00

0.750.50

5.002.003.001.501.501.50

8.40

7.358.506.00

5.754.25

0.50 2.00 0.50 2.00 5.00

n/an/an/an/an/an/an/a

Based on an average burdened labor rate of $8,000 per month, the total estimated project cost is $368,000 and the estimated effort is 46 person-months.

Tool-Based Estimation

51

project characteristicsproject characteristics

calibration factorscalibration factors

LOC/FP dataLOC/FP data

Estimation with Use-Cases

52

use cases scenarios pages   scenarios pages LOC LOC estimatee subsystem 6 10 6   12 5 560 3,366subsystem group 10 20 8   16 8 3100 31,233e subsystem group 5 6 5   10 6 1650 7,970

       stimate         42,568

User interface subsystem Engineering subsystem group Infrastructure subsystem group

Total LOC estimate

Using 620 LOC/pm as the average productivity for systems of this type and a burdened labor rate of $8000 per month, the cost per line of code is approximately $13. Based on the use-case estimate and the historical productivity data, the total estimated project cost is $552,000 and the estimated effort is 68 person-months.

Empirical Estimation Models

53

General form:

effort = tuning coefficient * sizeexponent

usually derivedas person-monthsof effort required

either a constant ora number derived based on complexity of project

usually LOC butmay also befunction point

empiricallyderived

COCOMO-II• COCOMO II is actually a hierarchy of estimation

models that address the following areas:• Application composition model. Used during the early stages of

software engineering, when prototyping of user interfaces, consideration of software and system interaction, assessment of performance, and evaluation of technology maturity are paramount.

• Early design stage model. Used once requirements have been stabilized and basic software architecture has been established.

• Post-architecture-stage model. Used during the construction of the software.

54

The Software Equation

55

A dynamic multivariable model

E = [LOC x B0.333/P]3 x (1/t4)where

E = effort in person-months or person-yearst = project duration in months or yearsB = “special skills factor”P = “productivity parameter”

Estimation for OO Projects-I• Develop estimates using effort decomposition, FP analysis, and any other

method that is applicable for conventional applications.• Using object-oriented analysis modeling (Chapter 8), develop use-cases

and determine a count. • From the analysis model, determine the number of key classes (called

analysis classes in Chapter 8).• Categorize the type of interface for the application and develop a

multiplier for support classes:– Interface type Multiplier– No GUI 2.0– Text-based user interface 2.25– GUI 2.5– Complex GUI 3.0

56

Estimation for OO Projects-II• Multiply the number of key classes (step 3) by the multiplier

to obtain an estimate for the number of support classes.• Multiply the total number of classes (key + support) by the

average number of work-units per class. Lorenz and Kidd suggest 15 to 20 person-days per class.

• Cross check the class-based estimate by multiplying the average number of work-units per use-case

57

The Make-Buy Decision

58

system Xsystem Xreusereuse

simple (0.30)simple (0.30)

difficult (0.70)difficult (0.70)

minorminor changeschanges

(0.40)(0.40)

majormajorchangeschanges

(0.60)(0.60)

simple (0.20)simple (0.20)

complex (0.80)complex (0.80)

majormajor changeschanges (0.30)(0.30)

minorminor changeschanges

(0.70)(0.70)

$380,000$380,000

$450,000$450,000

$275,000$275,000

$310,000$310,000

$490,000$490,000

$210,000$210,000

$400,000$400,000

buybuy

contractcontract

without changes (0.60)without changes (0.60)

with changes (0.40)with changes (0.40)

$350,000$350,000

$500,000$500,000

buildbuild

Computing Expected Cost

59

(path probability) x (estimated path cost) i i

For example, the expected cost to build is:

expected cost = 0.30 ($380K) + 0.70 ($450K)

similarly,

expected cost = $382K

expected cost = $267K

expected cost = $410K

build

reuse

buy

contr

expected cost =

= $429 K

Chapter 4.4

Project Scheduling

60

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

61

Effort and Delivery Time

62

Effort Cost

Impossible region

td

Ed

Tmin = 0.75T d

to

Eo

Ea = m (td4/ ta

4)

development time

Ea = effort in person-months

td = nominal delivery time for schedule

to = optimal development time (in terms of cost)

ta = actual delivery time desired

Scheduling Principles

63

• “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%40-50%

30-40%30-40%

15-20%15-20%

40-20-40 Distribution of Effort

• A recommended distribution of effort across the software process is 40% (analysis and design), 20% (coding), and 40% (testing)

• Work expended on project planning rarely accounts for more than 2 - 3% of the total effort

• Requirements analysis may comprise 10 - 25%– Effort spent on prototyping and project complexity may increase this

• Software design normally needs 20 – 25%• Coding should need only 15 - 20% based on the effort applied to

software design• Testing and subsequent debugging can account for 30 - 40%

– Safety or security-related software requires more time for testing

64

Basic Principles for Project Scheduling

• Compartmentalization– The project must be compartmentalized into a number of

manageable activities, actions, and tasks; both the product and the process are decomposed

• Interdependency– The interdependency of each compartmentalized activity,

action, or task must be determined– Some tasks must occur in sequence while others can occur in

parallel– Some actions or activities cannot commence until the work

product produced by another is available

65

Basic Principles for Project Scheduling

• Time allocation– Each task to be scheduled must be allocated some number of

work units– In addition, each task must be assigned a start date and a

completion date that are a function of the interdependencies– Start and stop dates are also established based on whether

work will be conducted on a full-time or part-time basis• Effort validation

– Every project has a defined number of people on the team– As time allocation occurs, the project manager must ensure that

no more than the allocated number of people have been scheduled at any given time

66

Basic Principles for Project Scheduling

• Defined responsibilities– Every task that is scheduled should be assigned to a specific

team member• Defined outcomes

– Every task that is scheduled should have a defined outcome for software projects such as a work product or part of a work product

– Work products are often combined in deliverables• Defined milestones

– Every task or group of tasks should be associated with a project milestone

– A milestone is accomplished when one or more work products has been reviewed for quality and has been approved 67

Relationship Between People and Effort

• Common management myth: If we fall behind schedule, we can always add more programmers and catch up later in the project– This practice actually has a disruptive effect and causes the

schedule to slip even further– The added people must learn the system– The people who teach them are the same people who were

earlier doing the work– During teaching, no work is being accomplished– Lines of communication (and the inherent delays) increase for

each new person added 68

Factors that Influence a Project’s Schedule

• Size of the project• Number of potential users• Mission criticality• Application longevity• Stability of requirements• Ease of customer/developer communication• Maturity of applicable technology• Performance constraints• Embedded and non-embedded characteristics• Project staff• Reengineering factors

69

Purpose of a Task Network• Also called an activity network• It is a graphic representation of the task flow for a project• It depicts task length, sequence, concurrency, and

dependency• Points out inter-task dependencies to help the manager

ensure continuous progress toward project completion• The critical path

– A single path leading from start to finish in a task network– It contains the sequence of tasks that must be completed on

schedule if the project as a whole is to be completed on schedule

– It also determines the minimum duration of the project70

Example Task Network

71

Task A3

Task B3

Task E8

Task F2

Task H5

Task C7

Task D5

Task I4

Task M0

Task N2

Task G3

Task J5

Task K3

Task L10

Where is the critical path and what tasks are on it?

Example Task Network

72

Critical path: A-B-C-E-K-L-M-N

Task A3

Task B3

Task E8

Task F2

Task H5

Task C7

Task D5

Task I4

Task M0

Task N2

Task G3

Task J5

Task K3

Task L10

Timeline Charts

73

Tasks Week 1 Week 2 Week 3 Week 4 Week n

Task 1

Task 2Task 3Task 4Task 5Task 6Task 7Task 8

Task 9Task 10Task 11Task 12

Use Automated Tools toDerive a Timeline Chart

74

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

Example Timeline Charts

75

Proposed Tasks for a Long-Distance Move of 8,000 lbs of Household Goods

76

Loadtruck

Unloadtruck

Drive truckfrom origin

to destination

Returntruck andsupplies

Decide on type/size ofrental truck

Reserverental truckand supplies

Arrange forworkers toload truck

Pick uprental truck

Arrange forworkers to

unload truck

Arrange forperson to

drive truck/car

Find lodgingwith space

to park truck

Make lodging

reservations

Determinedestination

locationDetermine

date to moveout or move in

Makedecisionto move

Packhousehold

goods

Plan travelroute and

overnight stops

Get moneyto pay forthe move

Lease or buyhome at

destination

• Where is the critical path and what tasks are on it?• Given a firm start date, on what date will the project be completed?• Given a firm stop date, when is the latest date that the project must start by?

Proposed Tasks for a Long-Distance Move of 8,000 lbs of Household Goods

77

17. Loadtruck

19. Unloadtruck

18. Drive truckfrom origin

to destination

20. Returntruck andsupplies

6. Decide on type/size ofrental truck

15. Reserverental truck

and supplies

7. Arrange forworkers toload truck

16. Pick uprental truck

9. Arrange forworkers to

unload truck

8. Arrange forperson to

drive truck/car

11. Milestone

13. Find lodgingwith space

to park truck

14. Make lodging

reservations

4. Determinedestination

location

3. Determinedate to move

out or move in

10. Packhousehold

goods

12. Plan travelroute and

overnight stops

2. Get moneyto pay forthe move

5. Lease or buyhome at

destination

• Where is the critical path and what tasks are on it? • Given a firm start date, on what date will the project be completed?• Given a firm stop date, when is the latest date that the project must start by?

Timeline Chart for Long Distance Move

78