Abstract
About 30% of our system accidents outside our company is due to misjudgment by our wrong "assumption". In our development process, the significant decisions are made by minimum group reviews so-called "inspection" and "walkthrough" about the requirements of contents and the scope of checking. According to one study of "assumption" mechanisms such reviews indeed make the miscalculation trend stronger. So, I studied "assumption" mechanisms of miscalculation by clarification of "assumption" rising condition and "assumption" promoting situation. I featured three main aspects as "assumption" rising condition. Next I consider the construction of well-appointed work processes hard to cause these conditions, and I have proposed them as countermeasures. I will continue the study by watching the effect of these measures in some proposed development process.
