The evolution of the evaluation of the effectiveness of the management of Protected Areas (EGAP) began in the 1990s, the first phase being led by university communities and non-governmental organizations (NGOs). In the second phase, EGAP evaluations became a way for funding agencies to assess performance. Thus, the Global Environment Facility (GEF) often required the establishment of a management effectiveness monitoring instrument (METT) as a condition for the renewal of funding (Coad et al. , 2015 cited by Pamela et al., 2017).

Various methods were used to measure the objective, leading to the development of the Management Effectiveness Monitoring Tool (METT), a simple questionnaire-type approach. This tool has become the most used in more than 2500 protected areas covering more than 4.2 million km 2 (more than a fifth of the world's terrestrial protected areas by area) in at least 127 countries. It is the 4th version of the METT. This tool was upgraded from METT-1 (2002) to METT-2 in 2005 to include better threat assessment. In 2007, for its growing interest in use by numerous institutions in all types of protected areas and biomes, based on its experience, WWF supported the development of the more detailed METT-3 version. It has remained the widely used or adapted version for over a decade.

In 2016, WWF published a manual for the METT-3 version. It contained various suggestions for revising and updating METT-3. Based on these suggestions, the METT-4
version was developed (Stolton and Dudley, 2016).