Skill Intensity and Regional Skill Change: Evidence from Online Job Advertisements for ICT Occupations

Online Job Advertisements (OJAs) represent a valuable resource for analysing labour demand in contemporary economies. In this paper, we use proprietary Lightcast data to study the demand for ICT professionals in Italy. The dataset provides one of the most comprehensive pictures of online labour demand, covering millions of job postings collected daily from a wide range of sources, including specialised job portals and company websites. We propose a novel approach to measure and map skill requirements for ICT occupations across Italian regions and provinces. Drawing on a Multilevel Item Response Theory (IRT) model, we construct a latent index of skill intensity for each job advertisement, capturing the overall level of skill requirements in a territory and enabling geographical comparisons over time and across space. The model also identifies the skills most critical in shaping labour demand for ICT professionals. We then examine changes in skill intensity over the 2021–2024 period and decompose them into within-occupation changes in skill requirements and compositional shifts in the occupational structure of labour demand. This paper contributes to the regional science literature on regional capabilities and to the labour economics literature on skill change and technological transformation by providing a territorially grounded measure of skill intensity and a framework to interpret its evolution.