[Kenneth Shadlen, Bhaven Sampat and Amy Kapczynski] Abstract ... We draw attention to the conceptual and methodological challenges of assessing the effects of patent provisions in trade agreements on prices and access to drugs, with particular emphasis on the importance of timing. Depending on when countries began allowing drugs to be patented, TRIPS-Plus provisions have different effects; and when pharmaceutical patenting has been in place for more countries for more time, the effects of TRIPS-Plus provisions will change again.