IPCC
A major strength of the IPCC process
has been the intergovernmental process, through reviews and then approval of the Summary for Policy Makers on a word-by-word basis. 
But it has also been subject to criticism as it is much more political.  In principle, this process is designed to provide a report in which the content is determined by the science while how it is stated is determined jointly with the governments.  Hence it aids communication between scientists and politicians.