Effective training in key communications5 stated that science policy relies ever more on public involvement and engagement, communication of science and dialogue, as well as on science and its social and ethical implications.Within this context, key actors in science -researchers and engineers, science institutions, and science centre and museum explainers -are increasingly being called upon to engage directly with the public. Various training programmes for public engagement with Science, Technology, Engineering and Mathematics (STEM) have been developed to provide both scientists and explainers with the support they need to be able to communicate effectively. However, to date each training programme has remained relatively isolated, pursuing its own path with little to no comparison between different programmes, and lacking an over-arching investigation of best practice.Comparative evaluation of communications training programmes is constricted by the wide diversity of course formats and delivery mechanisms. Programmes can range from external one-day training courses to in-house workshops at science centres and museums to formal degree programmes which usually take a