A global-scale systematic review (n = 241) assessed sustainable intensification (SI) technologies within smallholder agriculture; it considered multiple dimensions of performance and systematically assessed direction of response. Crop yield was overwhelmingly the top indicator. Monitoring gaps included few long-term studies (>3 years) and limited assessments of soil C stocks, food security, gender, labor, and wild biodiversity. SI interventions only produced positive responses for 70% of observations, and adjacent research sites often reported contrasting results. Monitoring of a wider range of SI domains is clearly needed, over longer time periods, with close attention to local adaptation.