  In this paper we introduce PerPaDa, a Persian paraphrase dataset that is
collected from users' input in a plagiarism detection system. As an implicit
crowdsourcing experience, we have gathered a large collection of original and
paraphrased sentences from Hamtajoo; a Persian plagiarism detection system, in
which users try to conceal cases of text re-use in their documents by
paraphrasing and re-submitting manuscripts for analysis. The compiled dataset
contains 2446 instances of paraphrasing. In order to improve the overall
quality of the collected data, some heuristics have been used to exclude
sentences that don't meet the proposed criteria. The introduced corpus is much
larger than the available datasets for the task of paraphrase identification in
Persian. Moreover, there is less bias in the data compared to the similar
datasets, since the users did not try some fixed predefined rules in order to
generate similar texts to their original inputs.
