Decisions are (usually) based on information. It seems to me that flawed information would lead to a flawed decision. Yet people with incomplete or flawed information often succeed. How is this possible?

First, I believe that factors other than rational assessment of information help guide decisions and greatly affect the success of human decision-making. Sociologists and psychologists probably investigate this more than do philosophers, although an approach to critical thinking championed by the Canadian philosopher Douglas Walton sheds some light on this through its emphasis on discussing critical thinking in terms of human dialogue that needs to be understood with reference to concepts like the "emotional dynamics" of a situation where two or more people are working hard together to make an important decision and of a general "context of dialogue" that involves more than the processing of information. Factors like those may explain why individuals with perfectly good information may fail to make a good decision if their emotional dynamics are horrible, as can occur when one of the interlocutors is belligerent or when the interlocutors misunderstand each other's expectations and needs. On the other...