Other institutions offer units in mediation across a number of disciplines such as law, social science, business and the humanities. Not all kinds of mediation-work require academic qualifications, as some deal more with practical skills than with theoretical knowledge. Membership organizations provide training courses. Internationally a similar approach to the training of mediators is taken by organizations such as the Centre for Effective Dispute Resolution, CEDR. Based in London, it has trained over 5000 CEDR mediators from different countries to date.