Testable Requirements as a Sizing Measure

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" rowspan="3" width=170 BGCOLOR="#000099" TEXT="#F7F7FF" background="02ebbc00erkqpg.jpg"> <div> <A HREF="tr_vs_test_cases.htm" TARGET="_top" TITLE="Testable Requirements Vs Test Cases"><IMG BORDER="0" SRC="Wing0a73007700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Testable Requirements Vs Test Cases</A></div> <div> <A HREF="new_paradigm_size_soft.htm" TARGET="_top" TITLE="A New Paradigm From Function Points or L"><IMG BORDER="0" SRC="Wing0a73007700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">A New Paradigm From Function Points or Lines of Code For Sizing Software Systems</A></div> <div> ------------------------------</div> <div> <A HREF="soft_size_meas.htm" TARGET="_top" TITLE="Software Sizing Measures"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Software Sizing Measures</A></div> <div> <A HREF="req_conc.htm" TARGET="_top" TITLE="Requirements Concepts"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Requirements Concepts</A></div> <div> <B><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Testable Requirements as a Sizing Measure</B></div> <div> <A HREF="tr_appl.htm" TARGET="_top" TITLE="Applications of Testable Requirements"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Applications of Testable Requirements</A></div> <div> <A HREF="tr_exper.htm" TARGET="_top" TITLE="Experience With Testable Requirements"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Experience With Testable Requirements</A></div> <div> <A HREF="ref.htm" TARGET="_top" TITLE="References"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">References</A></div> <div> <A HREF="glossry.htm" TARGET="_top" TITLE="Glossary"><IMG BORDER="0" SRC="Symb075c00b700c8cccccc00.png" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Glossary</A></div> </td> <td valign="top" colspan=2 height=60 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <B>Testable Requirements as a Sizing Measure</B></div> <bR> <bR> <div> </div> </td> </tr><tr> <td valign="top" height=396 width="100%" colspan=2 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> The concept of a <A HREF="test_req.htm" TARGET="_top" TITLE="Testable Requirements">testable requirement</A> has been used for years as a test of the quality and detail of system specifications.  <I><B>The key new assertion is that the number of testable requirements is a measure of the size of the system.  </B></I>This in turn has many practical applications to the measurement of the software development process.  </div> <bR> <div> The "testability" attribute of a requirement is the key concept that normalizes the requirement and makes the measure meaningful.  While the testability of a requirement is fundamental to the concept of sizing with testable requirements, it should be noted that sizing a system using testable requirements is <I>not</I> the same as counting test cases (<A HREF="tr_vs_test_cases.htm" TARGET="_top" TITLE="Testable Requirements Vs Test Cases">Testable Requirements Vs Test Cases</A>).</div> <bR> <div> Sizing a system based on testable requirements offers a flexible measure of software system size.  Since the <A HREF="req_conc.htm" TARGET="_top" TITLE="Requirements Concepts">definition of requirements</A> includes not only the traditional user requirements, but also other types of requirements, there is considerable flexibility to "size" either a complete system or selected aspects of a system.  For example:</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The user requirements</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The design requirements</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The requirements for a particular program</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The portion of the system that is being changed by a maintenance release</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The size of a software package</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">The size of modifications required to a software package.</div> <bR> <div> This raises the question: "What is meant by the size of a system?"  The answer depends on the individual perspective:</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">For an end user, the size is the number of user requirements (like Function Points).</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">For a programmer, the size may be the number of program requirements (like Lines Of Code).</div> <bR> <div> <IMG BORDER="0" SRC="Symb075c00b700f000000000.png" HEIGHT="16" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">For a manager or other estimator trying to project costs, the size may be the total of all types of requirements.</div> <bR> <div> Testable requirements provide a sizing measure that can address all these perspectives.  It offers <A HREF="new_paradigm_size_soft.htm" TARGET="_top" TITLE="A New Paradigm From Function Points or L">A New Paradigm For Sizing Software Systems</A> which has advantages over the other industry software measures, function points and lines of code.</div> </td> </tr><tr> <td valign="top" colspan=2 height=24 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <A HREF="req_conc.htm" TARGET="_top" TITLE="Requirements Concepts"><B><IMG SRC="02711110.png" border=0 width="17" height="17" ALT="prev" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></A><B> </B><A HREF="tr_appl.htm" TARGET="_top" TITLE="Applications of Testable Requirements"><B><IMG SRC="02811110.png" border=0 width="17" height="17" ALT="next" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></A><B>     </B><A HREF="index.htm" TARGET="_top" TITLE="Sizing Software Using Testable Requireme"><B><IMG SRC="02611110.png" border=0 width="17" height="17" ALT="up" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></A><B> </B><A HREF="tr_vs_test_cases.htm" TARGET="_top" TITLE="Testable Requirements Vs Test Cases"><B><IMG SRC="02c11110.png" border=0 width="17" 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