The following is really somewhat off topic...
... but if you care about congruence and have access to a good library I suggest you (whoever you are) have a look at a book written by Gerald M. Weinberg:
Quality Software Management Volume 3: Congruent Action http://www.dorsethouse.com/books/qsm3.html
Gerald M. Weinberg also has a website: http://www.geraldmweinberg.com/
Andreas