This article shows how new theoretical work on assessing sustainability of farms, carried out as part of a multidisciplinary approach, allowed a new theoretical framework to be develop, along with version 4 of the IDEA Method (Indicateurs de Durabilité d’une Exploitation Agricole). The first section divides existing studies taken from the literature into two types of indicator-based conceptual frameworks: those based on sustainable agriculture goals, and those based on a systemic approach focusing on the properties of sustainability as applied to agriculture. The second part of this article explains the overall process of assessing farm sustainability based on the conceptual framework developed for IDEA v.4. The theoretical framework relates to strong sustainability and agricultural multifunctionality (with 12 associated goals). It includes a systemic analysis of sustainability based on five properties characterizing a sustainable farm: The ability to produce and reproduce goods and services; Autonomy; Robustness, Territorial embeddedness and Global responsibility. This theoretical framework led to the proposal of 53 indicators structured / organized according to a double evaluative approach (and also two assesment grids). The first examines the extent to which sustainability has been achieved (in agro-ecological, socio-territorial and economic terms) by aggregating indicators based on 13 components and a scoring system using sustainability "units". The second approach assesses the level of sustainability based on the five properties mentioned above. Indicators are aggregated hierarchically. We discuss how the concept of properties has real educational value and can help to bring a new perspective to the field of sustainable farming.