This paper advances the measurement of nontariff measures (NTMs) by discussing a framework for how to compare regulations. We argue that relative differences in SPS regulations trigger the impact on trade flows between trading partner countries and specifically look at maximum residue levels (MRLs) for pesticides in a case study on Chilean fruit exports to the EU. In order to capture the relative differences and stringency in tolerance levels of trading partners, a simple indicator is constructed and applied in an econometric analysis. In comparison to existing indices of regulatory heterogeneity, the depth of information generated by our indicator severely compromises its coverage. Further development of our heterogeneity index will need to aim at including elements of process standards and conformity assessment procedures.