In general, ROUGE-1 and ROUGE-2 were considered as the baselines for validating the performance of AP because these variants strongly correlate with human evaluation methods (Owczarzak et al., 2012a,b).
the comparison could be repeated with ROUGE-3, ROUGE-4 and ROUGE-BE, which have been found to predict manual Pyramid better than ROUGE-1 and ROUGE-2 (Rankel et al., 2013).