This study is focused on the construction of a preliminary methodology that can well represent a complex phenomenon, such as the fragility of schools, allowing spatial and even temporal comparisons between Italian schools.

The aim is to provide the ‘best’ synthesis methodology from both a statistical and communicative point of view by examining alternative synthetic measures. In particular, this school-level indicator is designed to highlight potential problems within the education system and to provide a useful tool for intervention planning due to its immediate and effective interpretability.

The analysis is based on the following dimensions: family context, school context, geographical context of the schools and INVALSI (the National Institute for the Evaluation of the Education System) test results. For each dimension, elementary indicators were identified taking into account data availability and data quality.

The data in this study are obtained from multiple data sources, such as INVALSI and the Ministry of Education and Merit for the family context, school context and the test results dimensions. For the territorial context dimension, information is collected from the Revenue Agency and ISTAT (the Italian National Institute of Statistics). All Italian public schools with students enrolled in primary and lower secondary school classes that carried out the INVALSI tests, of grade 8, in the 2022/23 school year were considered, except for those of some autonomous regions.

The work involved the following steps, widely adopted in the literature, such as the collection of available data and construction of the elementary indicators, standardization, aggregation of the standardized indicators and finally the robustness and sensitivity check. It was decided to compare the following methods: the arithmetic mean, the geometric mean and the MPI index (Mazziotta-Pareto Index).

The results obtained with the different methods are very similar to each other; in fact, there are no substantial differences. However, compensatory methods in the construction of the indicator, such as MPI, could be a valid tool in the educational context that allows both simplicity and transparency of calculation as well as territorial comparability.

Keywords: Composite Index, INVALSI, Italian school system, Mazziotta-Pareto Index.