Function point analysis is a method of estimating the size of a software application based on the user view rather than lines of code. It involves identifying and classifying functional components such as internal logical files, external interface files, inputs, outputs, and inquiries. Each component is assigned a complexity and weight to calculate the total functional size in function points. The size can then be adjusted based on 14 general system characteristics to determine the final adjusted size. The document provides details on the history, vocabulary, types of data and transactions, counting process, and complexity determination involved in function point analysis.

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Function Point Analysis
Basics on estimation in functional points
By Svetlana Mukhina
Materials are adopted from David Consulting Group

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Introduction
Svetlana Mukhina
ICAgile ICP, ICP-ATF, ICP-BVA, PSM I, CSPO
Agile and Career Coach at Luxoft Agile Practice
Experience: 13+ years in IT, Project and department
management, Computer Linguistics, Technical Writing,
Quality Assurance
Interests: Project management, Agile transformation, Career
and performance coaching, Psychology
Hobbies: Horse riding, music, poker, travelling
https://www.linkedin.com/in/svetlanamukhina
https://www.facebook.com/Svetlana.Mukhina8

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Theoretical information on
Function Points

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Size
scale of task
in PF/SP/etc
Effort
man-hour
Duration
of project
Change
RFC
People
project team
Defects
quality
Critical
Resources
Estimating the Project Adopted from David Consulting Group

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History
• Function Point Analysis was developed first by Allan J. Albrecht in the mid 1970s
• The method was first published in 1979, then later in 1983
• In 1986 the International Function Point User Group (IFPUG) was set up
• Since 1987 membership in IFPUG has grown from 100 members to 600 members in 1997.
• In less than six years conference attendance has grown from 125 in 1988 to over 300 by 1997.
• Examination of IFPUG clearly indicates that the majority of its is members are from North
America
• There are numerous affiliate organizations of IFPUG. There are affiliate organizations in Italy,
France, Germany, Austria, India, The Netherlands, Australia, Japan, and several other countries.
from David Consulting Group

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Vocabulary – Main Terms
• is a unit of measure for quantifying software deliverable
(functionality) based upon the user view.Function Point
• is any person or thing that communicates or interacts with the
software at any timeUser
• is the Functional User Requirements as perceived by the userUser View
• are a subset of user requirements, that describe what the
software shall do (functions), in terms of tasks and services
Functional user
requirements
from David Consulting Group

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Vocabulary – Functional and Non-Functional Requirements
Functional (Include)
• Data Transfer (Input customer data, send control signal, send transactions
• from one system to another)
• Data Transformation (Calculate bank interest; derive average temperature; use billing data to produce invoice totals)
• Data Storage (Store customer order; record temperature over time; store control parameters to drive data)
• Data Retrieval (List current employees; retrieve satellite position; display a report of employee dependents)
Non-Functional (Exclude)
• Quality Constraints (Usability, Reliability, Efficiency, Portability)
• Organizational Constraints (locations for operations, target hardware, compliance to standards)
• Environmental Constraints (interoperability, security, privacy, safety)
• Implementation constraints (development language, delivery schedule)
from David Consulting Group

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• Function Points can be used to size software
applications accurately.
• FP can be counted by different people, at different
times, to obtain the same measure within a
reasonable margin of error
• FP can be estimated by proxy
• FP is easily understood by non-technical users
• FP can be used to determine whether a tool, a
language, an environment, is more productive when
compared with others
• Low risk of "inflation” comparing to lines of code or
story points methods
• LOC measures are not useful during early project
phases where estimating the number of lines of
code that will be delivered is challenging.
• FP can be derived from requirements
• Function points are not a very good measure when sizing
maintenance efforts (fixing problems) or when trying to
understand performance issues
• When maintenance programming is done by one or two
individuals, individual skill sets become a major factor when
measuring this type of work
• Development team don’t take part in estimation
Advantages and Disadvantages of Function Point Analysis
Adopted from David Consulting Group

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fromDavidConsultingGroup

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Practical Information on
Function Points

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Process of Function Point Estimation
Gather
available
documentation
Determine the
counting
scope,
boundaries,
functional user
requirements
Identify and
classify the
base functional
components
Calculate the
functional size
Document the
Function
Points
Report the
result
Measure the data functions
Internal Groupings of data called Internal Logical Files (ILF)
External Groupings of data or External Interface Files (EIF)
Measure the transactional functions
External Inputs (EI)
External Outputs (EO)
External Inquires (EQ)
Each function is assigned a functional complexity (L-A-H) and a
weight (FPs
Adopted from David Consulting Group

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Application Boundary
An application boundary is a conceptual interface between the software under study and its users.
• Scope of a project could include multiple applications.
• A functional size would be calculated for each affected application, in perspective to its boundary,
thereby producing its own count
• All affected application counts would be compiled to produce the total project count.
Adopted from David Consulting Group

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Types of Count
We count
• Installed application: Baseline (or
application) count
• Development project: New
system or subsystem
• Enhancement project: Add,
change or delete to present
system
We don’t count
• Corrective Maintenance –
Software maintenance performed
to correct faults in hardware or
software
• Perfective Maintenance –
Software maintenance performed
to improve the performance,
maintainability, or other attributes
of a computer program
• Non-functional requirements
from David Consulting Group

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Types of Data – Overview
Logical
View
Functionality
(ability to)
Logically
grouped stores
of data (data in
a form)
Elementary
process
(complete flow,
e.g. wizard)
Physical
View
Lines of code
Databases or
tables
Physical
transactions
(screens)
VS
FunctionPointsLookatLogicalView
Adopted from David Consulting Group

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Types of Data - Details
.
We count –
Business Data
•Reflects information needed to be stored
and retrieved by functional area addressed
by the application.
•Mandatory for the operation of the user’s
functional area
•User identifiable and maintainable
•Stores the user’s Core User Data to support
business transactions
•Very dynamic, business operations cause it
to be regularly referenced, added to,
changed, deleted
•Typically has key field and many attributes
•E.g Customer Data
We count –
Reference Data
•Stored to support business rules for the
maintenance of the business data.
•Mandatory for the operation of the user’s
functional area
•User identifiable and user maintainable
•Stores data to support core user activities
•Less dynamic – occasionally changes in
response to changes in the functional areas’
environment, external functional processes
and/or business rules
•Transactions processing business data
often use reference data
•Typically has key fields and few attributes
•E.g Policy information (Types and terms
of policies)
We don’t count –
Code Data
•Code data provides a list of valid value
values that a descriptive attribute might
have.
•Mandatory to the functional area, but
optionally stored as a data file to
standardize and facilitate business activities
and business transactions
•Not usually identified as part of the
functional requirements; it is usually
identified as part of design to meet technical
requirements
•Sometimes user maintainable, but
essentially static – only changes in response
to changes in the way that the business
operates
•Business transactions access Code Data to
improve ease of data entry, improve data
consistency, ensure data integrity, etc.
•Can be user recognizable as a group or
using the same logic
•Generally consists of a key field and one or
two attributes only
•Typically has a stable number of records
•Examples: Payment Type Code, Payment
Description
from David Consulting Group

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Internal Logical Files and External Interface Files
Application
Internal Logical File (ILF)
Data which is resides within the
application boundary and which is
maintained (added, changed, deleted,
updated) by the application
External Interface File (EIF) is a user
recognizable group of logically related data
or control information which is referenced by
the application being measured, but
maintained within the boundary of another
application. It is identified as an ILF in
another application(s)
Don’t count as an ILF or EIF:
• Files introduced because of technology or technical requirements
• Index files, Join/Merge Tables
• Prototypes, or files built but not used in application
• Temporary data files
• Copybooks, Work files, Sort files
• Separate physical entities if they are logically one data group
Adopted from David Consulting Group

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Exercise #1 – Counting Radio Alarm Clock
Inputs (EIs)
• Set time
• Set alarm
• Set type of alarm (radio, buzz) Set radio station
• Set volume of radio
• Set am/fm
• Set Snooze
• On/Off alarm
Outputs (EOs/EQs)
• Alarm
• Sound(Music/ Radio/Buzzer)
• Display Time
Internal Data Stores (ILFs)
• Time Data (Alarm Data/Time Data)
• Radio Data
External Data Sources (EIFs)
• Radio Frequency
from David Consulting Group

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Determine The Complexity and Weight
The number of ILFs, EIFs and their relative functional complexity determine the contribution of the data
functions to the functional size.
Each ILF and EIF will have an individual contribution based upon its functional complexity, to the total
number of function points for data function contribution to the project functional size.
Assign each identified ILF and EIF a functional complexity based upon the number of data element types
(DETs) and record element types (RETs) associated with the ILF or EIF.
Application
External Interface File (EIF)
RETs
DETs
DETs
DETs
Internal Logical File (ILF)
RET - A record element type (RET) is a
user recognizable subgroup of data
elements within an ILF or EIF
DET is a unique user recognizable,
non-repeated attribute
from David Consulting Group

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Type Low Avg High Total
EI _ X 3 + _ X 4 + _X6 =
EO _ X 4 + _ X 5 + _X7 =
EQ _ X 3 + _ X 4 + _X6 =
ILF _ X 7 + _ X 10 + _X15 =
EIF _ X 5 + _ X 7 + _X6 =
Function Point Counting Weights

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RETs 1-19
DETs
20-50
DETs
51+
DETs
1 Low Low Avg
2-5 Low Avg High
6+ Avg High High
ILF and EIF Complexity Matrix
EI Complexity Matrix
FTRs 1-4
DETs
5-15
DETs
16+
DETs
0-1 Low Low Avg
2 Low Avg High
3+ Avg High High
EO and EQ* Complexity Matrix
FTRs 1-5
DETs
6-19
DETs
20+
DETs
0-1 Low Low Avg
2-3 Low Avg High
4+ Avg High High

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Exercise #2 – Counting Application Data
from David Consulting Group

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Exercise #2 Results
from David Consulting Group

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Transactional Functions - Description
A transactional function is an elementary process that provides functionality to the user to process data
and is one of the following:
External Input (EI) – an elementary process that processes data or control information sent from outside
the boundary
- Words that suggest EIs: Add, Make Inactive, Allocate, Modify, Assign, Record, Associate, Remove, Change,
Reset, Create, Delete, Import, Reverse, Set, Undo, Update, Upload, Withdraw;
External Inquiry (EQ) – is an elementary process that sends data or control information outside the
boundary (using data retrieval only)
- Words That Suggest EQs: Browse Display Enquire Extract Inquire List Pick List View
External Output (EO) – is an elementary process that sends data or control information outside the
boundary and includes additional processing beyond that of an external inquiry.
- Words That Suggest EOs: Adjust Export Generate Notify Print Report Summary
Adopted from David Consulting Group

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Identifying Transactional Functions
from David Consulting Group

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Transactional Functions
Application
External Interface File
(EIF)
RETs
DETs
DETs
DETs
Internal Logical File (ILF)
RET - A record element type (RET) is a
user recognizable subgroup of data
elements within an ILF or EIF
DET is a unique user recognizable,
non-repeated attribute
User
EI = External Input
EO = External Output
EQ = External Inquiry
EI
EO
EQ
Adopted from David Consulting Group

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Exercise #3 – Counting Application Primary Processes and Data
Adopted from David Consulting Group

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Exercise #3 – Results
Description ILF/EIF/EI/EO/EQ FTRs DETs
Add EI 1 6
Change EI 1 6
Delete EI 1 5
Student Data ILF 1 4
16 FPs
Adopted from David Consulting Group

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General Systems Characteristics (GSCs)
GSCs are non-functional (technical) factors that can be applied to the unadjusted size measure to get an
adjusted functional size measure. The intent is to capture the effect of each driver on the development life
cycle environment. The value adjustment factor looks at 14 general system characteristics:
Data
Communication
Distributed
Data or
Processing
Performance
Objectives
Heavily Used
Configuration
Transaction
Rate
On-Line Data
Entry
End-User
Efficiency
On-Line Update
Complex
Processing
Reusability
Conversion &
Install Ease
Operational
Ease
Multiple-Site
Use
Facilitate
Change
Adopted from David Consulting Group

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Determine Value Adjustment Factor
Evaluate each of the 14
GSCs on a scale from 0 -5
to determine the degree of
influence (DI).
Calculate the degrees of
influence to produce total
degree of influence (TDI).
Insert the TDI into the
formula to produce the VAF
Formula: VAF=(TDI*0.01)+0.65

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Example of VAF Usage
If the functional project count was 100 fps, and the VAF was 1.1, then the adjusted count would be 110 fps.
Adjusted Function Points = Functional (Unadjusted) FP x VAF
 No system is rated at 0 on all GSCs; no system is rated 5 on all
GSCs; but if they were:
• All Zeroes VAF = (0*.01) +.65 = .65 All Fives VAF =
(70*.01)+.65 = 1.35
 Therefore, the VAF ranges from .65 - 1.35. In effect, using the
VAF can adjust the unadjusted (functional) size by + or - 35%.
Adopted from David Consulting Group

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Check List (process) for Counting Function Points
 Gather available documentation
 Determine the counting scope, boundaries and identify functional user requirements
 Identify and classify the base functional components
 Measure the data functions
 Internal Groupings of data called Internal Logical Files (ILF)
 External Groupings of data or External Interface Files (EIF)
 Measure the transactional functions
 External Inputs (EI)
 External Outputs (EO)
 External Inquires (EQ)
 Each function is assigned a functional complexity (L-A-H) and a weight (FPs)
 Calculate the functional size
 Add VAF (optional)

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Next Steps and Recommended Materials
Function Point Analysis Quiz and additional materials (for Luxoft Employees only) will be provided
in follow-up email
http://www.softwarevalue.com/insights/ - webinars and publication
http://www.softwarevalue.com/news/training/ - trainings

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Agile Events
Trainings: ICAgile Agile Team Facilitation – 30/06-01/07 in Kiev and 20/07-21/07 in Moscow
http://www.luxoft-training.ru/kurs/icagile_icp_agile_team_facilitation_icagile_icp-atf.html
Webinar:
Обзор сертификационного тренинга по фасилитации ICAgile Agile Team
Facilitationhttps://attendee.gotowebinar.com/register/5502311701820478468?source=webinar
7 main qualities of Agile team member https://attendee.gotowebinar.com/register/4051474223132743428?source=webinar
Что такое коучинг, чем коучинг не является и что такое Agile коучинг
https://attendee.gotowebinar.com/register/6313717198259291652?source=webinar
Встречи:
“Эксперементариум: фасилитация в реальном времени и контексте” – митап в Киеве
https://www.facebook.com/events/862901353855957/
IT Spring http://itspring.by conference in Minsk
IT Global Meetup in Saint Petersburg

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THANK YOU