The COLGEI project took place between September 2012 and March 2013. The international project was a survey of European sustainability indicators and their local implementation. The overall project can be broken down into four main parts:

1. Desk research. In order to get an overview of the current state of European indicator research, development and application, ICLEI conducted an extensive desk research over a period of two months.

2. Classification of the indicators. The findings were entered in an excel-file, listing the most relevant indicators in the following categories: human, social, natural and artificial.

3.Selection of cities. Selection of European frontrunner cities in the area of indicator development and sustainability. With this criteria the City of Aalborg, of Copenhagen, of Basel and of Lörrach were selected for exploratory visits.

4.Study visits. The city visits explored the specific indicator sets that were applied in each city The research concluded that even though a sustainable indicator set doesn’t exist on a European level, research showed that many pieces for such a set are already developed. In general, this project provided an overview of most important European indicator sets as well as city examples applying common and individual indicators in their daily working processes.