Software Estimation Techniques By: Kamalmeet Singh

What is Software Estimation? How much resources? How much time? How much effort? How much Cost?

How much resources?

How much time?

How much effort?

How much Cost?

Why do we need it? Would you like to start creating something without knowing the cost? Will it be better to buy/outsource than create?

Would you like to start creating something without knowing the cost?

Will it be better to buy/outsource than create?

Difficulties Premature estimations, if you don’t have the complete details Lack of Historical data Failure to follow the estimates: conditions prescribed in the estimate must not be violated Failure to update the estimates

Premature estimations, if you don’t have the complete details

Lack of Historical data

Failure to follow the estimates: conditions prescribed in the estimate must not be violated

Failure to update the estimates

How to do it?

Factors to be considered Product Objectives Corporate Assets Project Constraints

Product Objectives

Corporate Assets

Project Constraints

Product Objectives Scope: Capabilities to be provided by the software Quality: Performance Resource usage Compatibility with h/w and s/w Factors like – usability, security, safety, reliabilty and transportability

Scope:

Capabilities to be provided by the software

Quality:

Performance

Resource usage

Compatibility with h/w and s/w

Factors like – usability, security, safety, reliabilty and transportability

Corporate Assets People Process models Development tools Reusable software components Policies and procedures Workplace environment

People

Process models

Development tools

Reusable software components

Policies and procedures

Workplace environment

Project Constraints Design constraints Compatibility with h/w and s/w Memory and timing Implementation language Process constraints Number and type of people Development environment Scheduled delivery date

Design constraints

Compatibility with h/w and s/w

Memory and timing

Implementation language

Process constraints

Number and type of people

Development environment

Scheduled delivery date

What do we need to calculate? LOC (Lines Of Code) Or FP (Function Points)

LOC

(Lines Of Code)

Or

FP

(Function Points)

Function Point Analysis Function point count= UFP * VAM UFP: Unadjusted Function Point VAM: Value Adjustment Multiplier

Function point count= UFP * VAM

UFP: Unadjusted Function Point

VAM: Value Adjustment Multiplier

Unadjusted FP (UFPs) 1. External Inputs - data or control inputs (input files, tables, forms, screens, messages, etc.) to the system 2. External Outputs - data or control outputs from the system 3. External Inquiries - I/O queries which require a response (prompts, interrupts, calls, etc.) 4. External Interfaces - libraries or programs which are passed into and out of the system (I/O routines, sorting procedures, math libraries, run-time libraries, etc.) 5. Internal Data Files - groupings of data stored internally in the system (entities, internal control files, directories)

1. External Inputs - data or control inputs (input files, tables, forms, screens, messages, etc.) to the system

2. External Outputs - data or control outputs from the system

3. External Inquiries - I/O queries which require a response (prompts, interrupts, calls, etc.)

4. External Interfaces - libraries or programs which are passed into and out of the system (I/O routines, sorting procedures, math libraries, run-time libraries, etc.)

5. Internal Data Files - groupings of data stored internally in the system (entities, internal control files, directories)

UFP metrics

Value Adjustment Factors 1. data communications 2. distributed functions 3. performance 4. heavily used operational configuration 5. transaction rate 6. on-line data entry 7. design for end user efficiency 8. on-line update of logical internal files 9. complex processing 10. reusability of system code 11. installation ease 12. operational ease 13. multiple sites 14. ease of change

1. data communications

2. distributed functions

3. performance

4. heavily used operational configuration

5. transaction rate

6. on-line data entry

7. design for end user efficiency

8. on-line update of logical internal files

9. complex processing

10. reusability of system code

11. installation ease

12. operational ease

13. multiple sites

14. ease of change

Value Adjustment Multiplier 0 - factor not present or has no influence 1 - insignificant influence 2 - moderate influence 3 - average influence 4 - significant influence 5 - strong influence

0 - factor not present or has no influence

1 - insignificant influence

2 - moderate influence

3 - average influence

4 - significant influence

5 - strong influence

Calculating Effort Effort in Person Month For LOC E=5.2 * (KLOC)^0.91 [waltson-Felix model] E=5.5 + 0.73 * (KLOC)^1.16 [Bailey Basili model] E=3.2 * (KLOC)^1.05 [Boehm simple model] E=5.288 * (KLOC)^1.047 [Doty model for KLOC>9] For FP E=-13.39 + 0.0545 FP [Albert and Gaffney model] E=60.62 * 7.728 * 10^-8 FP^3 [Kermer model] E=585.7 +15.12 FP [Matso, Barnett and Mellichamp model]

Effort in Person Month

For LOC

E=5.2 * (KLOC)^0.91 [waltson-Felix model]

E=5.5 + 0.73 * (KLOC)^1.16 [Bailey Basili model]

E=3.2 * (KLOC)^1.05 [Boehm simple model]

E=5.288 * (KLOC)^1.047 [Doty model for KLOC>9]

For FP

E=-13.39 + 0.0545 FP [Albert and Gaffney model]

E=60.62 * 7.728 * 10^-8 FP^3 [Kermer model]

E=585.7 +15.12 FP [Matso, Barnett and Mellichamp model]

Models for Cost Estimation SDM- Software Development Model SLIM- Software Lifecycle Management COCOMO- Constructive Cost Model COCOMO II- COCOMO next version COPMO- Cooperative Programming Model

SDM- Software Development Model

SLIM- Software Lifecycle Management

COCOMO- Constructive Cost Model

COCOMO II- COCOMO next version

COPMO- Cooperative Programming Model

Basic COCOMO Model Organic projects - are relatively small, simple software projects in which small teams with good application experience work to a set of less than rigid requirements. Semi-detached projects - are intermediate (in size and complexity) software projects in which teams with mixed experience levels must meet a mix of rigid and less than rigid requirements. Embedded projects - are software projects that must be developed within a set of tight hardware, software, and operational constraints.

Organic projects - are relatively small, simple software projects in which small teams with good application experience work to a set of less than rigid requirements.

Semi-detached projects - are intermediate (in size and complexity) software projects in which teams with mixed experience levels must meet a mix of rigid and less than rigid requirements.

Embedded projects - are software projects that must be developed within a set of tight hardware, software, and operational constraints.

Basic COCOMO E=a(KLOC)^b D=c(E)^d P=E/D E- effort D- development time P- number of people Software project a b c d Organic 2.4 1.05 2.5 0.38 Semi-detached 3.0 1.12 2.5 0.35 Embedded 3.6 1.20 2.5 0.32

E=a(KLOC)^b

D=c(E)^d

P=E/D

E- effort

D- development time

P- number of people

Software project a b c d

Organic 2.4 1.05 2.5 0.38

Semi-detached 3.0 1.12 2.5 0.35

Embedded 3.6 1.20 2.5 0.32

Intermediate COCOMO E= a( KLOC)^ (b) * EAF Software project a b Organic 3.2 1.05 Semi-detached 3.0 1.12 Embedded 2.8 1.20 EAF: Effort Adjustment Factor

E= a( KLOC)^ (b) * EAF

Software project a b

Organic 3.2 1.05

Semi-detached 3.0 1.12

Embedded 2.8 1.20

EAF: Effort Adjustment Factor

EAF

Conclusion

Questions?

Thank You