Confirmation Bias - the tendency to notice evidence which supports your preexisting beliefs and ignore evidence which contradicts your beliefs. Also defined as: "the tendancy to retroactively emphasis evidence supporting an existing conclusion" (David Ford and Richard Paynting).
Confirmation bias is one explanation for why many management practices which are not effective continue. People selective filter results (unconsciously) to support their pre-existing beliefs and ignore evidence that such practices are ineffective. Adding that to the difficulty in evaluating many management practices mean confirmation bias is often the main factor determining what is accepted as a good practice.
Several methods can help counteract this tendancy such as prediction which is written down and then examined after the results are known. This helps avoid the tendancy for people to, after the fact, assume - that of course "these results are exactly what I expected."
Also just being aware that confirmation bias exists and attempting to examine your decision process in light of this helps a great deal.Related Terms: