From time to time each one of us is working on a different kind of operational issues with regards to GIS Science, trying to disseminate them through national and international GIS conferences. We lose valuable time and effort (and money of course) and we come into a project or work assessment that diminishes the overall level of the conference. Is there any kind of assessment of repetitive annual, or biennial international conferences that estimates its overall impact, as exists with the peer-reviewed journals with impact factor? How do you personally estimate the impact of such a conference with certain characteristics?