Increasing the employment rate is a core ambition for many European countries, not least because the ageing population is putting pressure on these countries' social security systems. The employment rate is defined as the percentage of employed individuals within certain age categories. This population includes three groups: the employed, the unemployed, and the inactive. The challenge of increasing the employment rate, therefore, involves addressing the employment of these two latter groups. While enhancing the employment rate is a prominent focus in government agreements, including those in Belgium, existing research has mainly concentrated on re-engaging the unemployed and has paid little attention to the thresholds that hinder the activation of inactive individuals in the labor market. This proposal for a junior research mandate aims to close this gap by investigating these thresholds and designing and evaluating a threshold-reducing intervention. More concretely, in the first phase, the multi- level predictors of inactivity will be studied – compared to those of unemployment – based on a combination of survey and administrative data. This analysis will give an insight into the relative proportion of personal characteristics versus national characteristics in the prediction of inactivity, unemployment, and employment. In addition, qualitative research will be conducted among inactive persons to further map the barriers to their activation. Then, an online vignette experiment will be set up where employed people, job seekers, and inactives will have to assess different jobs with different job characteristics on the extent to which they would be inclined to take them, as well as on statements about the perceived demands and resources of these jobs. This allows us, on the one hand, to examine how job seekers and inactive people evaluate jobs differently and, on the other hand, to identify the underlying mechanisms of their evaluations. In the final phase, based on the findings from the aforementioned research, a solution-oriented vignette experiment will be set up with nudges in the representation of job vacancies that make them more attractive to inactive people.