Cost_Estimation_Compatibility_Mode_

8/7/2019 Cost_Estimation_Compatibility_Mode_

1/18

Cost Estimation


2/18

One of the most difficult aspects of a

system analysts job has been the

accurate estimation of project size and

the development time.


3/18

Lines of Code

Lines-of-Codes is the oldest and most widely

used

A line of code is defined as a logical line, not

necessarily a physical line


4/18

Line Counting Rules

Comments do not count

Blank lines do not count Code that is included more than once counts only

the first time it is included. --- include files

Standard operating system include files do notcount

Code lines count

User defined include files count once

SQL statement count


5/18

Advantages

It is straightforward (simple)

Can be easily automated


6/18

Disadvantages

It is language dependent

Penalizes the well designed short programs

Cannot easily accommodate nonprocedural

languages Need a level of detail that may not be

available at the early stages of the

development.


7/18

Function Points

Allan J. Albrecht developed it in the mid 1970s.

It was an attempt:to overcome difficulties associated with lines of codes

as a measure of software size, and

to assist in developing a mechanism to predict effortassociated with software development.

One of the initial design criteria for function point

was to provide a mechanism that both softwaredevelopers and users could utilize to definefunctional requirements.


8/18

The Five Major Components

External Inputs (EI) is an elementary process in

which data crosses the boundary from outside toinside.

This data may come from a data input screen oranother application.

The data may be used to maintain one or moreinternal logical files.

The data can be either control information or business

information.If the data is control information it does not have to

update an internal logical file.


9/18

Components, cont

External Outputs (EO) an elementary

process in which derived data passes acrossthe boundary from inside to outside.

Additionally, an EO may update an internal logical

file (ILF).The data creates reports or output files sent to

other applications.

These reports and files are created from one ormore internal logical files and external interfacefiles.


10/18

Components, cont

External Inquiry (EQ) an elementary process

with both input and output components thatresult in data retrieval from one or more

internal logical files and external interface

files.

The input does not update any Internal Logical

Files, and output does not contain derived data.


11/18

Components, concluded

Internal Logical Files (ILF) a user identifiable

group of logically related data that residesentirely within the applications boundary and ismaintained through external inputs.

External Interface Files (EIF) a user identifiable

group of logically related data that is used forreference purposes only.The data resides entirely outside the application and is

maintained by another application.

The external interface file is an internal file foranother application


12/18

CountComplexity Components Total

Component Pessimistic

Most

likelyOptimistic

Estimated

CountLow Average High

External Inputs

3 4 6

External

Outputs4 5 7

External

Inquiries3 5 6

Internal LogicalFiles

7 10 15

External

interface Files

5 7 10

Total number of unadjusted function points (UAF)

Estimated Count = (Pessimistic + 4 Most likely + Optimistic) / 6


13/18

Value Adjustment Factor

The unadjusted function point count is

multiplied by the second adjustment factorcalled the Value Adjustment Factor.

This factor considers the systems technical ad

operational characteristics and is calculated by

answering 14 questions.

The factors are:


14/18

General SystemCharacteristics

Brief Description

Rate

(0 not

important to

5 very

important)

Data

Communications

The data and controlinformation used in the

application are sent or

received over communication

facilities

Distributed Data

processing

Distributed data or processing

functions are a characteristics

of the application within the

application boundary

On-line data entry

On-line data entry and control

information functions are

provided in the application.


15/18

Performance

Application performanceobjectives, stated or approved

by the user, in either response

or throughput, influence (or will

influence) the design,development, installation and

support of the application.

Heavily used

Configuration

A heavily used operational

configuration, requiring special

design consideration, is a

characteristic of the application.

Transaction Rate

The transaction rate is high andinfluences the design,

development, installation and

support.


16/18

End-user

Efficiency

The online functions provided emphasizes a

design for end-user efficiency

On-line UpdateThe application provides on-line update for

internal logical files.

Complex

processing

Complex processing is a characteristic of the

application.

Reusability

The application and the code in the

application have been specifically designed,

developed and supported to be usable in

other applications.

Installation Ease

Conversion and installation ease are a

characteristic of the application. A

conversion and installation plan and/or

conversion tools were provided and tested

during the system test phase.

Operation Ease

Operational ease is a characteristic of the

application. Effective start-up, back-up and

recovery procedures were provided and

tested during the system test phase.


17/18

Multiple Sites

The application has been

specifically designed, developed

and supported to be installed at

multiple sites for multipleorganizations.

Facilitate

Change

The application has been

specifically designed, developed

and supported to facilitate

change.

Total Rate

Complexity multiplier: C = (0.65 + 0.01 (Total Rate))

Function point count (FP) = UAF * C


18/18

Thank You!

Documents

Cost_Estimation_Compatibility_Mode_