Hannah Christine Simon defends her PhD thesis at the Department of Economics

Candidate:

Hannah Christine Simon, Department of Economics, University of Copenhagen

Title:

Search Frictions on Online Job Platforms: Evidence from High-Frequency Data

Supervisor:

• Steffen Altmann, Associate Professor, Department of Economics, University of Copenhagen

Assessment Committee:

• Mette Gørtz, Professor, Department of Economics, University of Copenhagen
• Lena Hensvik, Professor, Department of Economics, Uppsala University
• Didier Fouarge, Professor, Research Centre for Education and the Labour Market, Maastricht University

Summary:

This thesis consists of three self-contained chapters studying how visibility, behavioral frictions, and information design mediate job search, using high-frequency data from Denmark’s largest public job search platform.

The first chapter, written with Steffen Altmann, Malte Jacob Rattenborg and Alexander Sebald, investigates how the visibility of job postings shapes application behavior and firm recruitment. We show that doubling first-week clicks increases total applications by nearly 80 percent and pulls applications forward in time, without affecting applicant quality. These results indicate inefficiencies in firms’ posting practices and speak to the central role of visibility in firm hiring.

In the second chapter, I examine how gender differences in job search unfold from vacancy consideration to application submission. Conditional on opening a posting, women are about 15 percent less likely to apply relative to otherwise similar men. Women’s sorting into lower-wage and shorter-commute jobs arises primarily at the consideration stage, whereas selection into part-time positions intensifies as search progresses. These findings highlight that gender gaps in job search and in applied-for wages emerge from both vacancy selection and the scope of search.

The third chapter, written with Robert Mahlstedt and Alexander Sebald, turns to the design of search advice on platforms and asks whether more information helps or hinders job seekers. In a large-scale field experiment with more than 80,000 unemployed workers, we show that job seekers receiving simplified guidance are more optimistic, search more, and are more likely to find a job, all while experiencing smaller wage losses. These findings suggest that even potentially useful advice can lose effectiveness in a cognitively demanding informational environment.

Together, the three chapters show that the digital organization of job search is a key determinant of how labor markets function, with direct implications for firms, policymakers, and platform designers seeking to improve hiring efficiency and reduce inequality.

An electronic copy of the dissertation can be requested here: lema@econ.ku.dk