\PARstart{A}{ core} assumption in the business case
for IV\&V is the {\em leakage assumption}.

\begin{figure}
\footnotesize
\begin{tabular}{ll|rrrrr}\hline
&Issue &\multicolumn{6}{c}{Phase issue found}\\\cline{3-8}
&type &Requirements& Design& Code& Test& Integration& Ops \\\hline
&Requirements& 1& 5& 10& 50& 130& 368 \\
Phase&Design && 1& 2& 10& 26& 74 \\
issue&Code  &&& 1& 5& 13& 37 \\
resolved&Test   &&&& 1& 3& 7 \\
&Integration  &&&&&   1& 3\\
\end{tabular} 
\caption{``Leakage'' data from PITS. The longer an issue
remains unresolved, the more it cost to fix.}
\end{figure}
