Replication issues in syntax-based aspect extraction for opinion mining
Table 3: Optimal value of t for each corpus.
['[BOLD] Corpus', '[ITALIC] t∗']
As we mentioned earlier, to evaluate the impact of the t parameter whose value was not reported by \newciteliu_opinion_2012, we let the model return the unfiltered aspect candidates and evaluate the performance for t∈[10,20,...,tmax]. Note that tmax might be different each time. Because of this, the number of parameter configurations we tried for each corpora is slightly different. Instead of reporting each value, we rather report the average of per-corpus evaluated parameter settings, which was 1006. In this sense, when we experimented without setting a threshold we obtained a maximum recall of 0.697 —for the Nokia Phone corpus— but at the cost of precision 0.151. When we set t=10, we obtained a maximum precision of 0.9 but at the cost of recall being lower than five percent. These results mean the model does not seem to generalize well.