Many interpreters at historic sites seek to inform their visitors. But
how successful are they, and how can that success be monitored? This
paper examines whether a surrogate measure based on the communication
competency of the interpreter could be used. It suggests a means of me
asuring communication competency. However, rank correlations between i
nterpreters based on this measure, and measures of learnt information,
showed poor results. It is suggested that for future research the tec
hniques be applied to volunteers rather than trained interpretive staf
f, but even so, the measure of communication competency does present o
pportunities for staff training and monitoring.