One of the main indications of New Physics in rare $B$-decays is deduced from the tension between experimental and Standard Model predictions of the angular analysis of the $B^0 \to K^{*0} \mu^+\mu^-$ decay. There are however possible non-local hadronic effects which in principle can also explain these tensions. In this work, we consider a statistical approach for differentiating the source of the tension in $B^0 \to K^{*0} \mu^+\mu^-$ observables and we also investigate the prospects of such a comparison with future data from the LHCb experiment.