Abstract
The construction site and its elements create circumstances that are conducive to the formation of safety risks during the execution of works. Analysis indicates the critical importance of these factors in the set of characteristics that constitute the causes of accidents in the construction industry. The main substantive tasks in this article include isolating patterns of accidents on the site and identifying the analysed characteristics that are important in defining these patterns. In terms of methodology, the paper presents affinity analysis as the method of analysing data resources. The research was carried out on the basis of data from the register kept by the District Labour Inspectorate in Krakow (2014–2016).