“SOFTWARE ESTIMATION”

By: Rohit Sinha

Estimation and its Categories

• ESTIMATION - “Estimation is the process of finding an estimate, or approximation”.

• Software Estimation Techniques- 1) Delphi Technique.

2) Work Breakdown Structure (WBS).3) Three Point Estimation.4) Functional Point Method.

Why Measure Anything ?

• Primary purpose of any measurement program

CONTROL

MONITOR

MEASURE

HELP

Functional Point Analysis

• Function Point Analysis(agenda)Structured way of Problem Solving

Breaks into smaller component for better understanding and analysis

A unit of Measurement

To get average cost

Definition

• Function Point Analysis is a structured technique of problem solving. It is a method to break systems into smaller components, so they can be better understood and analyzed, and ultimately helps the project people with a unit of measurement which is nothing but “AVERAGE COST” .

How to count Function Point

5 step counting process

• Determine the type of count.• Identify the scope and boundary of the count.• Determine the unadjusted FP count.• Determine the Value Adjustment Factor.• Calculate the Adjusted FP Count.

Terms to understand

• User identifiable – It means defined requirements for processes and/or groups of data that are agreed upon, and understood by, both the users and software developers.

• Control information – It means the data that influences and elementary process of the application being counted. It tells us what, when, or how data is to be processed.

• Elementary process - An elementary process is the smallest unit of activity that is meaningful to the user.

Functional Point Mechanics

External Inputs(EI)

External Outputs(EO)

External Inquiries(EQ)

Internal Logical Files(ILF)

External Interface File(EIF)

Transaction Function

Data Function

External Input(EI)

• External input, is a process where the data crosses the boundary from outside to inside the application boundary.

ILFILF

Application boundary Database

External Output(EO)

• External Output, is a process where in the data comes “out” of the system.

• Means “DATA IS PROCESSED”

ILF ILF

Application boundary Database

External Enquiry(EQ)

• External Enquiry, is something which is fetched from the database and provided to the user with some sorting, indexing.

• Means “DATA IS NOT PROCESSED”

Search document

Internal Logical Files(ILF)

• ILF is a database entity which resides within the application boundary and which is maintained(added, changed, deleted, updated) by the application itself.

Application boundary

ILF ILF

External Interface File(EIF)

• EIF is any kind of file which the application cannot modify but can use the data for its use or to manipulate the result.

• Example : Tax calculation(VAT).

External database

Search results based on the info. processed by external database

Record Element Type(RET)

• A Record Element Type (RET) is the largest user identifiable subgroup of elements within an ILF or an EIF.

• The RET is calculated for the Data Functions.

File Type Reference(FTR)

• File Type Referenced (FTR) is the largest user identifiable subgroup within the EI, EO, or EQ.

• The transaction functions EI, EO, EQ are measured by counting FTRs and DETs that they contain.

Data element Type(DET)

• A data element type is a unique, user recognizable, non-repeated field.

• The DET concept need to apply when the analysis of data function and transaction function is carried out.

Visual representation

Process

ILF ILF

External Applications

Users

EO

EI

EQ

EIF EQ EI EO

Benefits

• Estimation(Functional point) Reduced cost by 15-20% by just measuring

Improves the communication of workloads

Improves the understanding of Business Function

Improves the allocation ofResources

Conclusion

• Function Points are becoming widely accepted as the standard metric for measuring software size.

Now that Function Points have made adequate sizing possible, it can now be anticipated that the overall rate of progress in software productivity and software quality will improve. Understanding software size is the key to understanding both productivity and quality.

Thanks for reading