## 5 Summary  
The article proposes a methodology of classifying the causes of occupational accidents involving construction scaffolding into generic groups that include technical, organizational, and human causes, as well as an assessment of the importance of causes in particular groups. The proposed methodology uses the Pareto-Lorenzo analysis, known in economics as the so-called ABC analysis. The application of the developed methodology was also presented using data on occupational accidents in Poland as an example. The application of the developed methodology in the analysis of occupational accidents involving construction scaffolding that took place in Poland, allowed the following causes of the greatest importance for occupational safety to be identified:  
* In the group of technical causes: a lack of or improper devices protecting workplaces on scaffolding, improper collective protection measures, improper stability of scaffolding or its components, and also improper spatial structure of scaffolding. * In the group of organizational causes, first and foremost: a lack of direct supervision by a construction manager or executive manager during the performance of work, approval of scaffolding for operation without the required inspections and supervisions, tolerance by the supervisors of derogations from the rules and regulations of occupational health and safety, a lack of or inadequate training of employees in occupational health and safety, giving permission to an employee to work with medical contraindications or without medical examination, and also a  
Figure 5: Pareto-Lorenz chart of identified human causes. lack of instructions for safe work on scaffolding or failure to familiarize with such instructions by employees. * In the group of human causes, first of all: failure to use personal protective equipment by an employee; disregard of a danger; inappropriate psychophysical state of an employee due to the consumption of alcohol, drugs or psychotropic substances; being surprised with an unexpected event; going to, driving through, or being in unauthorized places; arrogant and risky behavior of an employee causing disregard of a hazard, and also improper behavior of an employee due to ignorance of rules and regulations of occupational health and safety. The proposed methodology can be applied in both the area of scientific research and also in practice regarding the issues related to occupational safety management in the construction industry. It has a universal character, which means that it can be used in the research and analysis of causes of accidents that are related to not only scaffolding, but also to those that occur in different conditions and circumstances of construction works. The research and analysis results obtained with the aid of this methodology can be the basis for comparing accident rates in various construction areas, and also the basis for defining the most dangerous areas. Moreover, the proposed methodology can be used as a tool to compare accidents in different countries, regions, or enterprises. The practical aspect of the proposed methodology is connected to the possibility of drawing conclusions, which are important in accident prevention, on the basis of the obtained results. In particular, the determination of the validity of individual causes of accidents will allow the causes with the greatest importance for work safety to be indicated and preventive actions to be properly targeted. The results obtained using the developed methodology may also form the basis for formulating new legal regulations and modifying existing ones in the area of occupational safety. The above-mentioned activities will certainly contribute to the reduction of the accident rate and the achievement of the intended objective, which is zero accidents in the construction industry. The article is the result of the implementation by the authors of the research project No.