An observed precision and recall for positive and negative reviews is slightly different, especially when we compare a model using randomly generated lexicon (RAND) with the models using lexicons constructed in a controlled way (BASE, CPP-N).
the difference between rule-based propagation and CPP is small which may suggest that hybrid methods combining neural approaches with language resources are still imperfect for this  Table 6: Precision (P), recall (R) and F-score (F) for specific polarity classes, in the task of sentence-level sentiment recognition with LR-LSTM.