Scope and precision of sustainability assessment approaches to food systems

With sustainability within food systems becoming an increasingly important issue, several approaches that claim to assess the sustainability of farms, farming systems, and supply chains have been developed. Looking more closely at these sustainability impact assessment approaches, we discerned considerable differences between them in terms of scope, the level of assessment, and the precision of indicators used for impact assessment. Our aim was to classify and analyze a range of available sustainability impact assessment approaches with respect to scope and precision. From a total of 35 sustainability assessment approaches, we selected 6 for a detailed comparison. From our analysis, we concluded that there are 3 different types of trade-offs in these approaches: between different kinds of scope, between different indicators for precision and trade-offs, and between the scope and precision. Thus, one-size-fits-all solutions, with respect to tool selection, are rarely feasible. Furthermore, as indicator selection determines the assessment results, different and inconsistent indicators can lead to contradictory assessment results that may not be comparable. To overcome these shortcomings, sustainability impact assessments should include a precise definition of the notion of “sustainability” along with a description of the methodological approach and the indicator sets and should aim for harmonization of indicators and assumptions. Global initiatives such as the Sustainability Assessment in Food and Agriculture Systems (SAFA) Guidelines are a helpful step toward shedding light on the differences of these approaches and making the assessment results more comparable.