The Commission has adopted a guidance paper setting out criteria for the in-depth assessment of regional aid to large investment projects. The guidance outlines the kind of information required by the Commission for its detailed compatibility assessment and the assessment methodology, which is based on the balancing of the positive and negative effects of the aid. The guidance is in line with the Commission's refined economic approach to analysing State aid, based on the principles set out in the State Aid Action Plan. The guidance forms part of the Commission's efforts to clarify and refine the State aid rules.