A group of scientific organizations met under the aegis of the US National Academy of Sciences to discuss ways to improve the transparency of author contributions. The recommendations were based on feedback from stakeholders including universities, research institutions, funding agencies and scientific societies. Some of the recommendations have already been implemented by PLOS.
Reference link: http://www.stm-publishing.com/plos-collaborates-on-recommendations-to-improve-transparency-for-author-contributions/