Journal of Environmental Assessment Policy and Management Vol. 10, No. 1 (March 2008) pp. 1–24 © Imperial College Press WHAT APPEARS TO MAKE SEA EFFECTIVE IN DIFFERENT PLANNING SYSTEMS PAOLA GAZZOLA Department of Civic Design, University of Liverpool 74 Bedford Street South, Liverpool, L69 7ZQ, UK gazzola@liverpool.ac.uk Received 1 December 2006 Revised 14 January 2008 Accepted 18 January 2008 If Strategic Environmental Assessment (SEA) is to develop into an effective decision support instrument globally, then it should not just rely only on the input provided by a selected group of countries. In this context, the understanding of how to apply SEA effectively in different planning systems is unlikely to improve if the knowledge about those systems is limited. This paper establishes what appears to make SEA effective in two countries with different planning systems: Italy and the UK. Italy is chosen as an example, representing a specific Southern-European planning culture, which to date has not contributed to the SEA literature to any great extent. Based on empirical observations, it is suggested that the SEA effectiveness elements portrayed in the international literature are not fully valid. The UK is chosen as an example, which represents a specific Northern-European planning culture. Countries representing this planning culture have contributed heavily to the international SEA literature and have influenced the development of SEA theory strongly. In this context, the SEA effectiveness elements and benefits portrayed in the international literature appear to be valid. As part of a PhD research project, this paper builds on the findings of a content analysis of the international SEA literature (Fischer and Gazzola, 2006). Keywords: Northern-Europe; Southern-Europe; the UK; Italy; SEA effectiveness; planning cultures. Introduction To support practitioners worldwide in the development of effective and good prac- tice Strategic Environmental Assessment (SEA) and to help many countries conform to best international practice (Cherp and Antypas, 2003), a number of effectiveness 1