Function Point Analysis

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Function Point Analysis

• example

2
Function point

• FP is defined as one end-user business function
• FPA evaluates the system from a user perspective

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Function point

• 5 groups of FP
• Outputs
• Inquiries
• Inputs
• Files
• interfaces

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FP Calculations

• There is no universally acceptable standard to
  calculate FP. Therefore, different groups, or
  companies have their approach to making the
  calculation.
• Some approaches are more straight forward than
  others.
• The most important things to remember are
• to choose an approach and use it consistently.
• Collect data (estimate and actual) on all
  projects with the intent of improving project
  estimates
• We will use a simple approach to make the
  calculations

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Outputs

• Outputs are items of business info that is
  processed by the computer
• E.g., a report printed or otherwise

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Output Examples

• Transaction flies send to another application
• Customer invoices
• Accounts payable checks
• Punch cards
• User screen message
• Tape transaction
• Backup file
• Floppy disk transactions
• Etc.

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Inquiries

• Inquiries are when you ask a question that
  requires the use of a database, and these
  conditions are true
• solicit an immediate response,
• use simple keys, and
• perform no update function
• E.g., looking up a customer info
• E.g., Requesting info on a customer account
• Inquiries have an input part and an output part.
  Consider each separately.

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Inquiries example

• Suppose I want to find out about AA flight 73,
  this is an inquiry because it is a simple key,
  response immediate, and no update takes place.
• If we wanted to find out about all flights
  leaving Chicago between 9-11 am for New York,
  this would not be an inquiry because the key is
  no longer simple even though the other two
  conditions are true.

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Inputs

• Inputs are unique if
• It has a different format, or
• It has the same format as another input but
  requires different processing logic
• Suppose we had two input screens, each with the
  same format but different processing logic. We
  count each screen as a separate input.
• If the same two screens had identical processing
  logic, only one would be counted as an input.
• Suppose we have a screen whose function is to
  update a file. Since each of the three update
  functions (delete, change, add) requires
  different processing logic, we would have three
  update functions, not just one.

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Files

• Only stores that hold permanent data are
  considered logical files.
• Each logical view is considered a separate file.
• E.g., suppose we have a master customer file. One
  door (i.e., key) to the file is the cust and
  another door is the customer name. In this
  situation, we have two logical files.
• Also each logical user view into a database is
  considered a separate file.
• Suppose a database employs 5 different logical
  views for 26 users. We would count 5 logical
  files.

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Interfaces

• Interfaces are data, files, or control
  information within the application boundary that
  is sent to, shared with, or received from another
  application.
• Files shared between applications are counted as
  both files and interfaces within each application
  if they are used in both. Otherwise, file credit
  is given only to the application using,
  maintaining or doing the work on the file. The
  other application would receive no file credit
  but will receive interface credit.

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Interfaces Example

• Data or control info is passed from file A to
  file B. A receives credit for file and interface.
  B receives interface credit only.
• Data or control info is passed from file B to
  file A. B receives credit for file and interface.
  A receives interface credit only.
• Data or control info is shared between file A and
  file B. A and B would each receive both file and
  interface credit.

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Function point

• Each business function is classified and weighted
  by its level of complexity being
• Simple (low)
• Average (med)
• Complex (high)

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TABLES
INPUTS 1-4 FIELDS 5-15 FIELDS 16 FIELDS
0-1 FILES SIMPLE (3) SIMPLE (3) AVG (4)
2 FILES SIMPLE (3) AVG (4) COMPLEX (6)
3 FILES AVG (4) COMPLEX (6) COMPLEX (6)
INQUIRIES OUTPUT PART 1-5 FIELDS 6-19 FIELDS 20 FIELDS
0-1 FILES SIMPLE (4) SIMPLE (4) AVG (5)
2 FILES SIMPLE (4) AVG (5) COMPLEX (7)
3 FILES AVG (5) COMPLEX (7) COMPLEX (7)
15
TABLES
INQUIRIES INPUT PART 1-5 FIELDS 5-15 FIELDS 16 FIELDS
0-1 FILES SIMPLE (3) SIMPLE (3) AVG (4)
2 FILES SIMPLE (3) AVG (4) COMPLEX (6)
3 FILES AVG (4) COMPLEX (6) COMPLEX (6)
OUTPUTS 1-5 FIELDS 6-19 FIELDS 20 FIELDS
0-1 FILES SIMPLE (4) SIMPLE (4) AVG (5)
2-3FILES SIMPLE (4) AVG (5) COMPLEX (7)
4 FILES AVG (5) COMPLEX (7) COMPLEX (7)
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TABLES
FILES 1-19 FIELDS 20-50 FIELDS 51 FIELDS
1 FILES SIMPLE (7) SIMPLE (7) AVG (10)
2 FILES SIMPLE (7) AVG (10) COMPLEX (15)
3 FILES AVG (10) COMPLEX (15) COMPLEX (15)
INTERFACES 1-19 FIELDS 20-50 FIELDS 51 FIELDS
1 FILES SIMPLE (5) SIMPLE (5) AVG (7)
2 FILES SIMPLE (5) AVG (7) COMPLEX (10)
3 FILES AVG (7) COMPLEX (10) COMPLEX (10)
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Calculation

• See pg 62- 65 for formulas