A meical journal is a scientific journal devoted to the field of medicine. Most medical journals are peer-reviewed. Medical journals commonly arose as the journal of societies, such as the precursors of the British Medical Association, and would originally be collections of letters sent to the society by distant members, with an account of the proceedings of the society's recent meetings distributed to various members and the library. With the increase in science, medical research and activity, and publication, nobody can keep up, and in self defence articles picked by individuals are discussed in journal clubs at academic institutions. The prominence of medical journals is often determined by each journal's impact factor.