Evaluation studies should provide rich quantitative and qualitative data to understand the impact performance of different enterprises and social investments against the SDGs. Findings should be based on metrics that relate to the quantity and quality of effects. Data should be available in year on year formats for comparisons and be up to date. It should involve contextual data analysis, against targets, with timelines and trends, against benchmarks. While providing an evidence base for causal linkages, it requires the development of counterfactual, using control or comparison groups to measure what activity might have happened otherwise. Rigorous evaluation methods include Social Return on Investment (SROI), Quasi-experimental designs, Longitudinal and Cross Sectional Studies and Social Audits.