Development vs efficiency of Polish farms - trade-off or synergy effects?

he article aims to determine the nature of the relationship between farm development and its technical efficiency understood from the perspective of data envelopment analysis (DEA). The time scope of the analysis refers to the period 2004-2019. The empirical part of the article is based on the individual unpublished data for Polish farms conducting agricultural accounting according to Farm Accountancy Data Network (FADN). We employed a super-efficiency slack-based DEA model with variable returns to scale. This model enables us to compare and rank efficient farms as well as investigate the sources of farm (in)efficiency. We did not identify the substitution (trade-off) effect between farms` sustainability and efficiency. For level of technical efficiency and these differences were statistically significant. The main policy recommendation that can be derived from these results is that agricultural policy should support both efficiency improvements and progress toward higher sustainability.