Logical chains in territorial impact assessment

In a way similar to the established impact assessment system (e.g. EIA, SEA), territorial impact assessment (TIA) explores the causal links between proposed actions and impacts. TIA constitutes a case of special interest in impact assessment as it operates at an uncommonly high tier of proposed action – e.g. EU directives – with a wide reach of potential outcomes, at various scales. Recent TIA developments have been using a causality analysis technique known as ‘logical chains’, and it is precisely here that a recent experimental application of TIA encountered shortcomings capable of compromising TIA itself. The article reports on these shortcomings, conceptual and practical resolutions, as well as case-study feedback from stakeholders. •Territorial impact assessment project encounters shortcomings in logical chains.•EATIA project introduces formality in logical chains for impact assessment (TIA).•Formality in logical chains reduces uncertainty and enhances understanding.•The new, rigorous logical chains employ descriptive causal diagrams (DCD).•The national (PT) stakeholders work well with the new logical chains.