When is tutorial dialogue more effective than step-based tutoring?

It is often assumed that one-on-one dialogue with a tutor, which involves micro-steps, is more effective than conventional step-based tutoring. Although earlier research often has not supported this hypothesis, it may be because tutors often are not good at making micro-step decisions. In this paper, we compare a micro-step based NL-tutoring system that employs induced pedagogical policies, Cordillera, to a well-evaluated step-based ITS, Andes. Our overall conclusion is that the pairing of effective policies with a micro-step based system does significantly outperform a step-based system; however, there is no significant difference in the absence of effective policies. Moreover, while micro-step tutoring is more time-consuming, the findings still hold for five out of six learning performance measures when time on task is factored out.