Perception of semiquantitative terms in surgery.

Objective: To assess whether semiquantitative terms (eg, "often" or "rare"), which are often used for achieving informed consent, have the same meaning for laypersons and physicians.

Background: To obtain informed consent, physicians have to make their patients aware of the risks of an operation. Thereby, semiquantitative terms are often used.

Methods: Questionnaire interview among surgeons and randomly approached laypersons. A set of semiquantitative terms was presented to participants for quantification. Pertinent to 8 exemplary complications of common operations, these values were compared among the 2 interviewed groups and corresponding rates in scientific literature.

Results: The questionnaire was completed by 48 surgeons and 582 laypersons in Switzerland. Confronted with corresponding complication rates in literature, laypersons underestimated the risk significantly in 6 of 8 cases. After a simulated informed consent conversation with a surgeon by using semiquantitative terms, laypersons overestimated the complication rate significantly in 7 of 8 cases. An interaction analysis did not show any significant difference between correct estimations of complication rates of respondents who graduated, who had a professional medical background or who had had prior contact with the health care system (eg, medical consultation, hospitalization, operation) compared with the others.

Conclusions: Laypersons overestimate probabilities of semiquantitative terms named by surgeons. We recommend using "percentages" or "odds ratios" to achieve a more reliable preoperative informed consent.