Page 139 - DCAP304_DCAP515_SOFTWARE_PROJECT_MANAGEMENT

Unit 6: Effort Estimation

and FP is supposed to be proportional to effort or time required. Notes
(One Function Point = 2 days !)

Self Assessment

Fill in the blanks:
10. Function Point Analysis is a ……………………….. technique of problem solving.
11. The value adjustment factor (VAF) is based on 14 general system characteristics (GSCs)
that rate the general …………………………. of the application being counted.
12. The task of counting ……………………. should be included as part of the overall project
plan.

6.6 Functions Mark II

The MK II (Mark 2) Method is one of the software sizing methods in functional point group of
measurements. This is a method for analysis and measurement of information processing
applications based on end user functional view of the system. The MK II Method (ISO/IEC 20968
Software engineering—MK II Function Point Analysis—Counting Practices Manual) is one of
five currently recognized ISO standards for functionally sizing software.
The MK II Method were defined by Charles Symons in book published in 1991. UK Software
Metrics Association is now responsible for the method and its continuing development. The
functional user requirements of the software are identified and each one is categorized into one
of there types: inputs, exits and objects. In order to determine functional size of system these
functional requirements are counted.

Nolan, Norton & Co., part of KPMG Management Consulting, hired Charles Symons in 1984 to
advise clients on methods to improve their systems development performance. In the course of
doing this he claims to have discovered weaknesses in Albrecht’s approach to function point
analysis and developed the MK II approach to overcome them. By 1987 it became a licensed
product and is actively marketed.
Symons claims that the Albrecht approach suffers from the following weaknesses:
 It is often difficult to identify the components of an application. For example, what is a
logical file? In 1984, there was insufficient guidance to make these determinations.
 Albrecht had assigned weights to function point components based on “debate and trial.”
 The above two criticisms were also leveled at the identification and weighting of Value
Adjustment Factors.
 Albrecht did not provide a means of accounting for internal complexity. This is the same
problem regarding algorithms that the feature points technique was developed to address.

 When small systems are combined into larger applications, Albrecht’s approach makes
the total function point count less than the sum of the components.
The principal conceptual difference between the two methods is the calculation of Information
Processing Size, which corresponds to the Albrecht Unadjusted Function Points. Symons
decomposes the application being counted into a collection of logical transactions. Each
transaction consists of an input, a process and an output. For each transaction, Unadjusted Function
Points (UFP) become a function of the number of input data element-types, entity-types referenced
and output data element-types. The UFPs for the entire system are then summed.

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