write:Extrapolating was a mistake. We were forecasting based on theinformation in front of us—WYSIATI—but the chapters we wrote first wereprobably easier than others and our commitm

which I call irrational perseverance: the folly we displayed thatday in failing to abandon the project. Facing a choice
we gave uprationality rather than give up the enterprise.Drawn to the Inside ViewOn that long-ago Friday
our curriculum expert made two judgments aboutthe same problem and arrived at very different answers. The inside view isthe one that all of us
including Seymour
spontaneously adopted to assessthe future of our project. We focused on our specific circumstances andsearched for evidence in our own experiences. We had a sketchy plan: weknew how many chapters we were going to write
and we had an idea ofhow long it had taken us to write the two that we had already done. Themore cautious among us probably added a few months to their estimateas a margin of error.Extrapolating was a mistake. We were forecasting based on theinformation in front of us—WYSIATI—but the chapters we wrote first wereprobably easier than others
and our commitment to the project wasprobably then at its peak. But the main problem was that we failed to allowfor what Donald Rumsfeld famously called the “unknown unknowns.” Therewas no way for us to foresee
that day
the succession of events that wouldcause the project to drag out for so long. The divorces
the illnesses
thecrises of coordination with bureaucracies that delayed the work could notbe anticipated. Such events not only cause the writing of chapters to slowdown
they also produce long periods during which little or no progress ismade at all. The same must have been true
of course
for the other teamsthat Seymour knew about. The members of those teams were also unableto imagine the events that would cause them to spend seven years tofinish
or ultimately fail to finish
a project that they evidently had thoughtwas very feasible. Like us
they did not know the odds they were facing.There are many ways for any plan to fail
and although most of them are tooimprobable to be anticipated
the likelihood that something will go wrongin a big project is high.The second question I asked Seymour directed his attention away fromus and toward a class of similar cases. Seymour estimated the base rateof success in that reference class: 40% failure and seven to ten years for