The most unsuccessful three years in the education of cost estimators appears to be fifth-grade artihmetic - Norman R. Augustine
Augustine is former Chairman and CEO of Martin Marietta. His seminal book Augustine's Laws, describes the complexities and conundrums of today's business management and offers solutions. Anyone interested in learning how successful management of complex technology based firms is done, should read that book. As well, read McConnell's book and see if you can find where
Because I sure can't find that proof or any mention that estimates don't work, other than for those who failed to pay attention in the 5th grade arithmetic class.