BLIND CHANCE - AN INVESTIGATION INTO THE PERCEIVED PROBABILITIES OF PHRASES USED IN ORAL RADIOLOGY FOR EXPRESSING CHANCE

The necessity for numerical probabilities in oral radiographic diagnos is is increasing, due to recent developments in computer-aided diagnos is, decision analysis, informed consent and medical litigation. These numerical probabilities are only partly available from current texts o n oral radiology, where they are often expressed by ill-defined, semiq uantitative phrases. Therefore, in this study 30 phrases expressing th e probability of a relationship between a diagnosis and its symptoms w ere taken from a selected textbook on oral radiology. Seven oral radio logists from the USA and the Netherlands scored each of these probabil istic phrases on a 20-cm visual analogue scale. Low intraradiologist a nd high interradiologist variation was found. Because the high variati on among authors of texts on oral radiology in interpreting probabilit y information could have a negative influence on their ability to tran sfer unambiguous information to their readers, it is recommended that the use of semiquantitative phrases in oral radiology is restricted to five probability groups.