The phenomenon of misconduct in scientific research illustrates how great can be the social damage of not knowing the incidence of a malady. Many urgings about such phenomenon have predicated views about the extent of institutional and governmental vigilance on observers' differing surmises about how frequently misconduct occurs. Such is the measurement error of extant data about incidence1 that one can venture little more than the deliberately imprecise conclusion that “misconduct is neither common nor rare.”.