This paper focuses on the use of a linguistics-based method for automatic object-oriented sentiment analyses. The study was conducted as part of SentiRuEval automatic sentiment analysis system testing cycle. The original task was to extract users’ opinions (positive, negative, neutral) about telecom companies, expressed in tweets and news. In this study news was excluded from the dataset because, being formal texts, news significantly differs from informal ones in its structure and vocabulary and therefore demands a different approach. Only linguistic approach based on syntactic and semantic analysis was used. In this approach, a sentiment-bearing word or expression is linked to its target object at either of two stages, which perform successively. The first stage includes usage of semantic templates matching the dependence tree, and the second stage involves heuristics for linking sentiment expressions and their target objects when syntactic relations between them do not exist. No machine learning was used. The method showed a very high quality, which roughly coincides with the best results of machine learning methods and hybrid approaches.

The paper describes our approach to the task of sentiment analysis of tweets within SentiRuEval – an open evaluation of sentiment analysis systems for the Russian language. We took part in the task of sentiment analysis of Russian tweets concerning two types of organizations: banks and telecommunications companies. On both datasets, the participants were required to perform a three-way classification of tweets: positive, negative or neutral.

We used various statistical methods as basis for our machine learning algorithms. Linguistic features produced by our morpho-syntactic analyzer are applied to the classification. Syntactic relations proved to be a crucial feature for any statistical method evaluated, and SVM-based classification performed better than the others. Normalized words are another important feature for the algorithm.

The evaluation revealed that our method proved to be rather successful: we scored the first in three out of four evaluation measures.