In the entire collection, no more than 30 reviews are allowed for any
given movie because reviews for the same movie tend to have correlated
ratings. Further, the train and test sets contain a disjoint set of
movies, so no significant performance is obtained by memorizing
movie-unique terms and their associated with observed labels. In the
labeled train/test sets, a negative review has a score <= 4 out of 10,
and a positive review has a score >= 7 out of 10. Thus reviews with
more neutral ratings are not included in the train/test sets. In the
unsupervised set, reviews of any rating are included and there are an
even number of reviews > 5 and <= 5.
When using this dataset, please cite the ACL 2011 paper
InProceedings{maas-EtAl:2011:ACL-HLT2011,
author = {Maas, Andrew L. and Daly, Raymond E. and Pham, Peter T. and Huang, Dan and Ng, Andrew Y. and Potts, Christopher},
title = {Learning Word Vectors for Sentiment Analysis},
booktitle = {Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies},
month = {June},
year = {2011},
address = {Portland, Oregon, USA},
publisher = {Association for Computational Linguistics},
pages = {142--150},
url = {http://www.aclweb.org/anthology/P11-1015}
}