The "Declaration on Regionalism" in Europe was adopted by the AER in 1996 during the General Meeting of European Regions in Basel (CH). It is a reference document for new regions or those undergoing expansion. It defines the norms and criteria for regional development and fixes the different steps to be undertaken so that the region can beacknowledged as a fully-fledged political entity.

In 2006 the AER drafted a Regionalism Report and respective Country Reports. The Regionalism Report is the first stage in an ambitious project to understand how regionalism works in practice across Europe. It is based on the AER Declaration on Regionalism in Europe published in 1997.

The AER launched the 'Subsidiarity is a word' movement to demand recognition of the word subsidiarity and the inclusion of the word in every dictionary of every language worldwide. Although the definition of “subsidiarity” may differ slightly between dictionaries and languages, the word in its political context can be defined generically as “the principle that decisions should be taken as closely as possible to the citizen”.
 

The Draft European Charter on Regional Democracy was initiated by the Council of Europe's Congress of Local and Regional Authorities in Europe (CLRAE) in 1997. The original idea behind the Charter was to set out the key principles that should underlie effective regional democracy in Europe, covering areas such as financial autonomy and legislative powers.

It is one of the key missions of the AER to promote the principle of subsidiarity and regional democracy in the wider Europea and beyond. Whereas regional democracy is already an established institutional structure in most of the Western European countries, states belonging to the former Communist block are still quite centralised. AER is engaged in promoting the principles of regional democracy, good governance and stability in the EU's Eastern neighbour countries. AER therefore is actively engaged in the newly launched EU policy scheme of the Eastern Partnership (EaP). 

AER studies aim at gaining deeper knowledge on the links between the competences and powers of European regions and their overall regional performance in the European context.The studies collect data and retrieve information and to convert it into indicators that reflect the current situation of regions across European countries. 

In order to facilitate knowledge on the latest developments regarding regional democracy and regionalisation trends, the AER is organising together with interested regions seminars and conferences on this topic.