\PARstart{I}sssues
of sampling bias threaten any data
mining experiment; i.e. what matters {\em there} may not be true {\em here}.
All of the data used here comes from NASA and NASA
works in a particularly unique market niche. Nevertheless, we argue
that results from NASA are relevant to the general software engineering
industry. NASA makes extensive use of contractors.
These contractors service many
other industries. 
These contractors are contractually
obliged (ISO-9001) to demonstrate their understanding and usage of
current industrial best practices. 
 For these reasons, other noted researchers such
as Basili, Zelbowitz, et.al.~\cite{basili02} have argued that
conclusions from NASA data are relevant to the general software
engineering industry.

More specifically,
all the data discussed here comes from independent V\&V which, as noted by
Wallace \& Fugii, is very different to other kinds of V\&V. Certainly, 
there are differences:
\bi
\item
Embedded V\&V is typically conducted in-house by analysts who
report to the same managers as the developers. In this environment,
developers feel that that they are on the same team as the  V\&V analysts.
Hence,  
developers usually give V\&V analysts extensive information on the project.
\item
Since they report to different management structures,
the potential is there for developers to misunderstand, even distrust, the goals
of the independent V\&V analysts,
Hence, IV\&V teams typically have access to much less data than their embedded
counterparts.
\ei
On the other hand, embedded and independent V\&V analysts use the
same tools and methods (but might focus on different parts of the system).
According to the definition by the NASA Safety and 
Mission Quality Office, IV\&V is \ldots \begin{quote}{\em A process whereby the 
products of the software development life cycle phases are 
independently reviewed, verified, and validated by an 
organization that is neither the developer nor the acquirer 
of the software.  IV\&V differs from V\&V only in that it is 
performed by an independent organization.~\cite{nasa92}.}\end{quote}
Under that assumption,
lessons from IV\&V also apply to embedded V\&V.

 
