The Cancode interaction analysis system in the oncological setting: reliability and validity of video and audio tape coding

Cancode is a computerized interaction analysis system developed for cancer consultations. This paper assesses its reliability and validity, and compares the use of audio versus video tape; by assessing 30 consultations between an actor and 10 oncologists. Weighted Kappa inter- and intra-rater scores ranged from 0.5 to 1.0 and 0.58-1.0, respectively, and use of video tape did not alter verbal coding. Factor analysis of verbal codes revealed two factors, 'verbal control' and 'verbal support'. Verbal and non-verbal doctor behavior differed by patient type ('verbal support' P = 0.007, 'verbal control' P = 0.004, 'Responsiveness' P = 0.000, and 'Immediacy' P = 0.000). Inter-doctor variation was noted for 'verbal support' (P = 0.000) and 'Relaxation' (P = 0.000). 'Responsiveness' was negatively correlated with 'verbal support' (-0.58) and 'verbal control' (-0.65). Cancode is reliable, valid and sensitive to doctors behavioral changes. For a more passive patient, the doctor may switch from a 'cure' to 'care' oriented consult, responding to psycho-social instead of informational needs.