As a next step, we checked if scores can be a good heuristic for prioritizing nodes corresponding to partial solutions. Well-prioritized nodes would preferably select routes that are more promising for further search and boost the efficiency of retrosynthesis planning. To this end, we checked if synthetic accessibility scores can detect potentially infeasible partial synthesis routes. We assessed this by taking all pairs of internal and not solved siblings nodes and checking if the average score of internal nodes is greater than the score of not solved nodes (cf. Figure ). We used a one-sample t-test for score differences of node pairs. The alternative hypothesis was that the mean of the pair differences distribution is greater than 0. We checked also if incorporating in-stock set molecules would not bias the node statistics. Thus, we repeated the same test on node scores incorporating only expandable molecules. Results are depicted in Figure . Practically, all scores with at least one aggregating statistic can correctly discriminate internal nodes from not solved and solved nodes from not solved. Omitting the set of in-stock molecules did not change the results.