of vacancies associated with a job posting. Job descriptions are a key source of data for skill demand, and the paper mostly focuses on analyzing them.

Job postings data, however, may not be representative of labor demand across entire economies. Recent evidence from the roll-out of LinkedIn data for policy use (e.g., at the World Bank) suggests that online job platform data are skewed towards high-skilled jobs and that the degree of labor market representativeness highly varies across countries (Zhu et al., 2018). Correcting for such bias is not straightforward. Kureková et al. (2015) highlight that due to the absence of information on the precise size and structure of the population of vacancies in the job market of many countries, traditional correction methods (e.g., weighting) are often not feasible to achieve representativeness. In the case of Kosovo, we highlight three aspects with regard to representativeness. First, close to 40 percent of the employed population is estimated to work informally (i.e., without a labor contract).<sup>14</sup> Assessing the extent to which this leads to a bias in representativeness is difficult, as traditional data sets at the firm level (such as firm registries) do not reflect jobs created in the informal sector, therefore compromising comparisons with job portals data. Second, and similar to other middle-income countries, even within the formal sector not all vacancies appear on job portals, in part because the majority of jobs tend to be filled through informal channels (Cojocaru, 2017; World Bank, 2019a). Employers report that informal channels are their main recruitment channel, with 64 percent using such channels to recruit for high-skilled positions, and 59 percent for medium- to low-skilled positions (World Bank, 2019a). Finally, because online job advertisement is carried out by both private and public providers, even among online vacancies the true number and characteristics of posted jobs are not known. Kureková et al. (2015) stress that vacancies tend to occur in the presence of an unfulfilled demand or where employers have preferences for a selection process. Therefore, online vacancies are useful to learn about jobs for which employers face difficulties to fill through internal or informal search channels.<sup>15</sup> To examine which segments of the labor market are observed on job portals, we contrast findings from our vacancy analysis with other evidence from the Kosovar labor market using labor force survey data in Section V.<sup>16</sup> Despite their limitations, job portal data are a complement to other available data, especially to understand which profiles are in demand. For instance, Labor Force Surveys (LFS) are useful to analyze overall variations in employment across sectors and age groups, but these data have limitations in reliably and timely estimating job creation and the characteristics of jobs currently created. More importantly, LFS data reflect the stock of available skills in the labor force, while job postings directly express employer needs and the skills in demand.

> 14 World Bank calculation based on LFS 2017. Informality is defined here as workers without a labor/employment contract (legal definition in Kosovo).

> 15 Anecdotal evidence from counterparty discussions suggests that this is increasingly true in Pristina, the capital city of Kosovo.

> 16 The 2017 LFS is used to compare the characteristics of jobs on the portals with the characteristics of employment in the economy. STEP Employer survey data (World Bank, 2019a) are used to contrast our findings on skills.

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