In order to identify descriptions of materials and reaction conditions that provide noticeable acetylene conversion, we applied SGD. We searched for SGs of catalysts and conditions that present a narrow distribution of X C2H2 . In the present dataset, the majority of situations associated with noticeable activity correspond to X C2H2 values close to 1.0 (Fig. ). Removing data points with X C2H2 = 0 and S = 0 from the SISSO modelling prevents that the uninteresting yet numerous situations associated to zero activity dominate the selection of models for selectivity, as the root-mean-squared loss (objective) function of SISSO reflects the average performance across the entire training data. Thus, the loss function would be strongly affected by the data points with X C2H2 = 0 and S = 0. Besides, by considering a narrow, nonzero conversion range, a proper comparison of selectivity across materials and reaction conditions is possible (see next section).