  Learning from demonstration (LfD) is commonly considered to be a natural and
intuitive way to allow novice users to teach motor skills to robots. However,
it is important to acknowledge that the effectiveness of LfD is heavily
dependent on the quality of teaching, something that may not be assured with
novices. It remains an open question as to the most effective way of guiding
demonstrators to produce informative demonstrations beyond ad hoc advice for
specific teaching tasks. To this end, this paper investigates the use of
machine teaching to derive an index for determining the quality of
demonstrations and evaluates its use in guiding and training novices to become
better teachers. Experiments with a simple learner robot suggest that guidance
and training of teachers through the proposed approach can lead to up to 66.5%
decrease in error in the learnt skill.
