## 4 Conclusions  
The need of defining a reliable method for assessing the seismic vulnerability of existing buildings is crucial in order to prevent damages and subsequent economic loss, both in ordinary conditions, through the adoption of an adequate maintenance program, and extraordinary conditions, such as the emergency phases following an earthquake. Since an important aim is the estimation of the consequences of a seismic event on a territory, several methodologies are available in the literature aimed to provide an assessment of the seismic vulnerability on a 'large scale' by means of simplified analyses. This paper was firstly focused on the analysis of some simplified methods proposed in the literature for assessing the 'large scale' seismic vulnerability, with a particular focus on those most suitable for the typical Italian buildings heritage. The selected methods are different in type and number of input data, type of output, limitations of use for different structural typologies, complexity of use, computational effort, and type of final judgment. The main idea of the paper was to verify the possibility of providing reliable large scale vulnerability judgments based on a minimum set of information, already available in the local or national platform and without the necessity of carrying out additional surveys, i.e., 'at zero cost' in terms of time and resources. This means that the preliminary large scale vulnerability assessment could be carried  
Figure 13: Overall comparison of vulnerability judgments coming from methods of Group A and B.  
out only based on few data made available by administrative offices and not coming by additional technical surveys. According to such an approach, the choice of a suitable method for assessing the seismic vulnerability on a large scale should be also consistent with the available knowledge level of the buildings and, thus, not all the methods are reliable or applicable in the case of a lack of necessary information. The methods selected according to the above criteria were then applied to a sample of school buildings located in the province of Naples (Italy), characterized by an almost uniform seismic hazard. Buildings were different mainly in structural typology, geometry, and age of construction. The structural data necessary for applying vulnerability methods were not obtained by onsite surveys directly carried out by the authors, but came from a regional digital platform. Depending on the information necessary for the application of each method, the reference sample of buildings was customized according to the level of knowledge available. The methods were divided into two macrocategories: Group A with the most simplified methods, which require a reduced number of parameters, and Group B with more detailed methods, which need more data. Methods of Group A provide a vulnerability judgment related to the assignment of a 'vulnerability class', while methods of Group B generally provide a quantitative evaluation based on safety indexes. Some methods of Group B associate a vulnerability judgment to the safety index too. It is worth noting that most methods of Group B are applicable to masonry structures only. The comparison between the results obtained from the application of the different methods allows one to highlight the following items:  
1. Full database (935 buildings, application of method of Group A): * For masonry buildings (228), SAVE and DM58/17 methods gave comparable vulnerability classes (high-medium), with the results of SAVE being slightly more conservative. The S&C approach judged the buildings almost equally distributed in three classes (low, medium, and high vulnerability); * For RC buildings (707)--unlike masonry buildings--the SAVE method resulted in being unsafe, since it provided a low vulnerability class for all the buildings of the set. This result was not likely given the heterogeneity of the construction age of the different buildings in the set, which included both old buildings and recently designed buildings.