\PARstart{T}{he} IV\&V Facility in Fairmont, West Virginia is responsible for verifying that software developed or acquired to 
support NASA missions complies with the stated requirements. Additionally, the Facility validates that the software 
is suitable for its intended use. In short, the Facility ensures 
that the software is being developed properly, and that the 
right software is being developed or acquired. 

XXX established by the challenger investigation committee

As the sole entity with the responsibility for IV\&V of all NASA
mission software, the IV\&V Facility is in a unique position to
create and maintain a master repository of software metrics. Under
this charter, the IV\&V Facility reviews requirements, code, and
test results from NASA's most critical projects; hence, many of the
required metrics are collected as a matter of course. No other
organization has insight into such a broad range of NASA projects.
This affords the IV\&V Facility an unequalled opportunity to research
not only the early life cycle indicators of software quality, but
other topics as well. Many large corporations have similar software
metrics repositories; however, it is not always in their best
interest to release data or results to the public. In the case of
the IV\&V Facility, the objective is to improve NASA's mission
software regardless of the source. Once NASA projects agree to
distribution, then sanitized data1 would be made available to NASA,
industry, and academia to support software development and research
by other organizations. For example, the data used in this study
is freely available,
on-line\footnote{\url{http://promisedata.org/repository/data/silap}}.


IV\&V is often confused with V\&V.



XXX does iV\&V work? roi studies. hinkles' ISS stories (where the contractor
asked for more iv\&V. IV\&V as the corporate memory

A core assumption in the business case
for IV\&V is the {\em leakage assumption}. \fig{leakage}
shows PITS data relating to the cost of a fixing an issue.
All the rows are costs relative to the cost of fixing
an issue in the phase where it was first found. In a result
consistent with numerous other researchers (e.g.~\cite{kan95}), 
the PITS
data shows that the cost of fixing an issue increases dramatically,
the longer it stays in the system.
Even if IV\&V finds the {\em same} issues as the projects,
it adds value to the NASA organization if it does so {\em sooner}
than the projects.

\begin{figure}
\footnotesize
\begin{tabular}{l@{~}|l|r@{~}r@{~}r@{~}r@{~}r@{~}r|}\cline{2-8}
&Issue &\multicolumn{6}{c|}{Phase issue found}\\\cline{3-8}
&type &Req'ments& Design& Code& Test& Integration& Ops \\\cline{2-8}
&Req'ments& 1& 5& 10& 50& 130& 368 \\
Phase&Design && 1& 2& 10& 26& 74 \\
issue&Code  &&& 1& 5& 13& 37 \\
re-&Test   &&&& 1& 3& 7 \\
solved&Integration  &&&&&   1& 3\\\cline{2-8}
\end{tabular} 
\caption{``Leakage'' data from PITS. The longer an issue
remains unresolved, the more it cost to fix.}\label{fig:leakage}
\end{figure}


