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<td><font size="7"><p align="CENTER"></font><font face="Arial" size="6" color="#008000"><strong>Function
Points Step by Step</strong></font></p>
<p align="center"><font face="Arial"><small> </small><font size="4"><b>by <a href="mailto:David@SoftwareMetrics.Com">David Longstreet</a></b></font></font></p>
<p align="center"> </p>
<u><b><p><font face="Arial" color="#008000">ABSTRACT</font></b></u></p>
<p><font face="Arial">Many individuals struggle with counting function points even though
they understand the function point counting rules. This article describes the necessary
steps to complete a function point count. Additionally, the necessary documentation needed
to complete a function point count is discussed. The counting process should utilize
existing application and project documentation. The Step by Step counting process should
be used in association with <u>Function Point Counting Practices Manual</u>, Release 4.0,
by IFPUG.</font></p>
<u><b><p><font face="Arial" color="#008000">OBJECTIVES OF FUNCTION POINT ANALYSIS</font></b></u></p>
<p><font face="Arial">To provide accurate sizing, as early as possible, that can be used
as an input into the estimating process.</font></p>
<p><font face="Arial">To provide a mechanism to track and monitor scope creep. Function
point counts at the end of requirements, analysis, design, code, testing and
implementation can be compared. The function point count at the end of requirements and/or
designs can be compared to function points actually delivered. If the project has grown,
there has been scope creep. The amount of growth is an indication of how well requirements
were gathered by and/or communicated to the project team. If the amount of growth of
projects declines over time it is a natural assumption that communications with the user
has improved.</font></p>
<u><b><p><font face="Arial" color="#008000">KEY DELIVERABLES</font></b></u></p>
<p><font face="Arial">Key deliverables from a Function Point Count are:</font><ul>
<li><font face="Arial">Total Unadjusted Function Point Count</font></li>
<li><font face="Arial">The Unadjusted function point count by EI, EO, EQ, ILF and
EIF’s.</font></li>
<li><font face="Arial">The Value Adjustment Factor (VAF).</font></li>
<li><font face="Arial">The total adjusted function point count.</font></li>
<li><font face="Arial">Validation reports -- as prescribed in step 8.</font></li>
</ul>
<u><b><p><font face="Arial" color="#008000">KEY INPUTS</font></b></u></p>
<p><font face="Arial">Depending on the phase of the project the following documents will
be needed.</font><ul>
<li><font face="Arial">Documentation of the users’ perceived objectives, problems and
needs.</font></li>
<li><font face="Arial">Collected documentation regarding the current system, if such a
system (either automated or manual) exits.</font></li>
<li><font face="Arial">Any refined objectives and constraints for the proposed system.</font></li>
<li><font face="Arial">Any other requirement documentation completed to date.</font></li>
<li><font face="Arial">Screen Formats and dialogues</font></li>
<li><font face="Arial">Report Layouts</font></li>
<li><font face="Arial">Layouts of input forms</font></li>
<li><font face="Arial">Interfaces with other systems and between systems</font></li>
<li><font face="Arial">Logical and/or preliminary physical data models</font></li>
</ul>
<u><b><p><font face="Arial" color="#008000">KEY ASSUMPTIONS</font></b></u></p>
<p><font face="Arial">The following assumptions are made:</font><ul>
<li><font face="Arial">The <u>Function Point Counting Practices Manual</u>, Release 4.0, by
IFPUG is used.</font></li>
</ul>
<ul>
<li><font face="Arial">The person completing the function point count has received training
in function points prior to counting. Ideally, the application expert will count function
points with the assistance of an Function Point Counting Expert.</font></li>
</ul>
<b><p><font face="Arial">Initial Steps</font></b></p>
<p><font face="Arial">Prior to counting function points the application boundaries must be
determined. The application boundary should be drawn around the entire application, not
individual project teams. The function point counting expert and the application
functionality expert need to work together to determine the boundary. The result of this
initial step will be a boundary diagram. Refer to chapter 4, pp. 4-1 through 4-4, <u>Function
Point Counting Practices Manual</u>, Release 4.0 by IFPUG. Drawing of the application
boundary is a critical step in counting function points. This boundary will determine
additional the inputs into Checkpoint, a tool used for estimating.</font></p>
<b><p><font face="Arial">Step 1 - Planning the Function Point Count</font></b></p>
<p><font face="Arial">The task of counting function points should be included in the
overall project plan. That is, counting function points should be scheduled and planned.
The first function point count should be developed to provide sizing used for estimating.</font></p>
<p><font face="Arial">Function points can be counted prior to the completion of
requirements. The function point counts completed early in the life cycle should be
thoroughly documented, so they can be easily maintained and updated. Of course, early
estimates using function points (or any method) are subject to change as much as the
requirements. In short, if the scope and size of the project changes, the effort required
to complete the project will change also. Function point analysis can be completed prior
to having a complete set of requirements, but a function point count should be completed
after the requirements have been finalized and again at implementation.</font></p>
<p><font face="Arial">After the function point count has been completed it should be
compared to previous function point counts to verify any new components or changed
components and the function point count updated accordingly. Each addition to the function
point count should have an attached label indicating if the new component or changed
component is the result of changed functionality or if it is the result of improved
function point counting.</font></p>
<b><p><font face="Arial">Step 2 - Gathering the documentation</font></b></p>
<p><font face="Arial">The following recommended documentation will assist in completing
function points counts prior to the finalization of requirements.</font></p>
<p> </p>
<blockquote>
<blockquote>
<p><font face="Arial">Documentation of the users’ perceived objectives, problems and
needs.</font></p>
<p><font face="Arial">Collected documentation regarding the current system, if such a
system (either automated or manual) exits.</font></p>
<p><font face="Arial">Any refined objectives and constraints for the proposed system.</font></p>
<p><font face="Arial">Description and/or model of the overall system framework.</font></p>
<p><font face="Arial">Any other requirement documentation completed to date. </font></p>
</blockquote>
</blockquote>
<p><font face="Arial">A more detail function point can be completed after analysis and
design. Recommended documentation during and after the completion design.</font></p>
<blockquote>
<blockquote>
<p><font face="Arial">Screen Formats and dialogues</font></p>
<p><font face="Arial">Report Layouts</font></p>
<p><font face="Arial">Layouts of input forms</font></p>
<p><font face="Arial">Interfaces with other systems and between systems</font></p>
<p><font face="Arial">Logical and/or preliminary physical data models </font></p>
<p><font face="Arial">Filed sizes and formats</font></p>
<p><font face="Arial">Menu Options</font></p>
</blockquote>
</blockquote>
<p><font face="Arial">The function point counts completed prior to design should be
compared to the function point counts after the completion design. This will be an
indicator of how much the application has grown since requirements.</font></p>
<p><font face="Arial">Recommend documentation at the conclusion or implementation of the
project should include all the above mentioned documentation and any additional system
documentation.</font></p>
<b><p><font face="Arial">Step 3 - Determine the Value Adjustment Factor</font></b></p>
<p><font face="Arial">Determine the Value Adjustment Factor (VAF). The VAF should be
reviewed during the initial stages of function point counting. As the count proceeds the
VAF can be updated as necessary and as more information is discovered. The VAF should be
reviewed and updated at the completion of each subsequent step.</font></p>
<p><font face="Arial">The value adjustment factor (VAF) is based on 14 general system
characteristics (GSCs) that rate the general functionality of the application being
counted. Each characteristic has associated descriptions that help determine the degrees
of influence of the characteristics. The degrees of influence range on a scale of zero to
five, from no influence to strong influence. The IFPUG <u>Counting Practices Manual</u>
provides detailed evaluation criteria for each of the GSC, the table below is intended to
provide an overview of each GSC.</font></p>
<table border="1" cellspacing="1" cellpadding="7" width="565">
<tr>
<td width="41%" valign="TOP" colspan="2"><font face="Arial">General System Characteristic</font></td>
<td width="59%" valign="TOP"><p align="CENTER"><font face="Arial">Brief Description</font></td>
</tr>
<tr>
<td width="7%" valign="TOP"><font face="Arial">1.</font></td>
<td width="34%" valign="TOP"><font face="Arial">Data communications</font></td>
<td width="59%" valign="TOP"><font face="Arial">How many communication facilities are
there to aid in the transfer or exchange of information with the application or system?</font></td>
</tr>
<tr>
<td width="7%" valign="TOP"><font face="Arial">2.</font></td>
<td width="34%" valign="TOP"><font face="Arial">Distributed data processing</font></td>
<td width="59%" valign="TOP"><font face="Arial">How are distributed data and processing
functions handled?</font></td>
</tr>
<tr>
<td width="7%" valign="TOP"><font face="Arial">3.</font></td>
<td width="34%" valign="TOP"><font face="Arial">Performance</font></td>
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