Function Point Analysis: Size Matters - No Matter What You Have Been Told!

Knowledge Solution Services:
Size Matters – Regardless of What You
Have Been Told!

David Herron
David Consulting Group
d.herron@davidconsultinggroup.com

Challenges Project Managers Face Today
• Shifting Priorities
–Scope
–Schedule
• Unrealistic Expectations
–Customer
–Service Management
• Lack of Performance
–Productivity
–Skill Levels
• Inability to Properly Manage the Project
©2012 David Consulting Group 1

What Does the Customer Want?
We manage the customer;
and, we manage the project.

Customer’s Needs Manager’s Challenge
Quicker Shifting Priorities
Time to market Schedules
Requirements
Better Expectations
Functional Quality Availability
Reliability
Cheaper Performance
Lowest Possible Cost Outsourcing


What Do We Use to Measure Projects?

What We Manage What We Measure
Shifting Priorities Schedule
Schedules
Requirements Cost
Expectations
Quality
Availability
Reliability
Project Deliverables
Performance
Outsourcing


Basis of Measures
You Manage… By Monitoring… Based On…

Schedule Plan vs Estimated scope
Actual

Costs Plan vs Scope, resources
Actual

Project Features, Requirements
Deliverables Functions

Quality Defects Removal Efficiency

Where Did You Go Wrong?
• You’ve estimated the scope and created a project
plan
• You’ve determined the cost of the project based
on scope and available resources
• The requirements have been documented
• You are inspecting code and removing defects

… And your project still comes in late, over budget
and with poor quality!


Managing All the Pieces

DELIVERABLE
SCHEDULE

Is There
Something
Missing?

COST QUALITY


Size Does Matter
• Finding: Nine out of 10 projects that fail have not
been sized properly

• Consider: When you build a house you specify all
the functions and features you want – those are
your requirements. The builder then generates an
estimate based on the size (square footage) of
your requirements.

• Size is the key to effectively managing software
projects

Tracking Performance Without Size

Project Cost Quality
(000’s) (Defects Released)

PO Special $500 12
Vendor Mods $760 18
Pricing Adj. $80 5
Store Sys. $990 22


Tracking Performance With Size

Project Size Cost Rate Quality Density
(Functional Value) (000’s) (Defects
Released)
PO 250 $500 $2,000 12 .048
Special
Vendor 765 $760 $993 18 .023
Mods
Pricing 100 $80 $800 5 .050
Adj.
Store Sys. 1498 $990 $660 22 .014


Characteristics of Effective Sizing
• Meaningful to developer and user
• Defined (industry recognized)
• Consistent (methodology)
• Easy to learn and apply
• Accurate, statistically based
• Available when needed (early)
• Addresses project-level information needs


Why Function Points?
Function Point Analysis is the standardized method for
measuring the functionality delivered to the end user.

• Consistent method
• Easy to learn
• Available early in the lifecycle
• Acceptable level of accuracy
• Meaningful internally and externally

Function Points have replaced Line of Code counts as a
sizing metric that can be used consistently and
with a high degree of accuracy.


The Function Point Methodology
The software deliverable is sized based upon the
functionality delivered.
Five key components are
• Inputs identified based on logical user view

• Outputs Input Inquiry Output

• Inquiries
• Data Stores
Data
• Interface Files Stores

Interface Application
File


Functionality Identified

PURCHASE
USER USER ORDER
Input SYSTEM
Inputs ADD, CHG
PAYMENTS
INVOICES
Interface
PURCHASE
ORDER INFO
PAYMENTS
INVOICES
Inquiry
VENDOR
Data Stores USER

PAYMENT
STATUS
ACCOUNTS PAYABLE
Output
USER

PAID
INVOICES


Determine the Functional Size
COMPONENTS ARE ASSESSED BASED UPON COMPLEXITY:
Data Element Types (Fields or Attributes)
File Types Referenced (Data Stores)
Record Element Types (Data Sub-Groups)
(Note: Details are not known to us so we assume average values)

Complexity

Components: Low Avg. High Total

Data Stores X7 3
X 10 X 15 30
Interfaces X5 1 X 7 X 10 7
Inputs X3 3 X 4 X 6 12
Outputs X4 1 X 5 X 7 5
Inquiries X3 1 X 4 X 6 4
58
Function Point Size


Other Quantitative Measures
• Level of Effort
– Project Manager
– Staff Personnel
– Overtime
– Company Meetings
• Duration (Time to Market)
– Project stoppage
– Concept
– Requirements through first delivery
• Quality (Defect Density)
– Post release defects
– Defects by phase
– Entry point, discovery point, fix point

Estimating Using Delivery Rates

DEFINITION CAPABILITY

ESTIMATES
PROJECT PROJECT DELIVERY =
SIZE COMPLEXITY RATE
– Effort

Function Points Profiles

58 11 FP/PM 5.3
Person Months


Utilization of Function Points
Function point size reflects the business functionality
being delivered to the customer. The size value is
available for use in conjunction with numerous
measures to quantify and to evaluate software
delivery and performance.

For Example:
Development Cost per Function Point
Support Cost per Function Point
Delivered Defects per Function Point
Function Points per Staff Month
Project Delivery Rate (Hours per Function Point)
Portfolio Function Points supported by one FTE
Speed of Delivery or Function Points per Elapsed Month


Size Makes the Difference
• Size makes standard project measures more
meaningful
• Function Point Analysis is an effective sizing
technique
• Performance measures can be developed using
Function Points as a base measure


Contact Us
Email: d.herron@davidconsultinggroup.com

Phone: 1-610-644-2856, ext 21

http://www.davidconsultinggroup.com

@DavidConsultGrp
/DavidConsultGrp
/company/David-Consulting-Group


Function Point Analysis: Size Matters - No Matter What You Have Been Told!

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