Short texts like advertisements are characterised by a number of slogans, phrases, words, symbols etc. To improve the quality of textual data, it is necessary to filter out noise textual data from important data. The aim of this work is to determine to what extent it is necessary to carry out the time consuming data pre-processing in the process of discovering sequential patterns in English and Slovak advertisement corpora. For this purpose, an experiment was conducted focusing on data pre-processing in these two comparable corpora. We try to find out to what extent removing the stop words has an influence on a quantity and quality of extracted rules. Stop words removal has no impact on the quantity and quality of extracted rules in English as well as in Slovak advertisement corpora. Only language has a significant impact on the quantity and quality of extracted rules.
natural language processing; comparable corpora; text mining; data pre-processing; stop words; sequence rule analysis