Effective for National Science Foundation (NSF) grant proposals submitted or due on or after January 14, 2013, there is a new Grant Proposal Guide NSF 13-1 . For proposals submitted prior to January 14, 2013, the guidelines in GPG 11-1 apply.  There are significant changes for the “merit review criteria, review and revisions” which can be located at http://www.nsf.gov/pubs/policydocs/pappguide/nsf13001/gpg_sigchanges.jsp.