Research & Publications
by PhDr. Oliver Scharfenberg.

PhDr. Oliver Scharfenberg, CEO of Syntharis Group, researches trust signals and their effect on decisions. His main topics are employer seals and applicant behavior, seals of quality and consumer behavior, employer branding and recruiting, and, more recently, visibility in AI search. His doctoral dissertation (DTI University, 2024) analyzed the market for employer seals in Germany and their influence on applicant behavior. His work combines such empirical studies, including an experiment with 1,093 participants, with practical guides for employers.

Eleven of his publications are listed on ResearchGate, including articles in the International Journal of Progressive Research in Engineering Management and Science, his doctoral dissertation and two books published in 2026.

A credible employer seal makes people noticeably more likely to apply. In the experiment with 1,093 participants, adding the seal to a job ad raised the share of people who were likely to apply from 37.96% to 53.95%, an increase of almost 16 percentage points. The share of people who were unlikely to apply fell from 17.88% to 6.04%.

The study also shows the condition: applicants trust seals that are based on a representative employee survey and transparent award criteria. Seals that rely on self-assessment or can simply be bought offer much less credibility.

The 1,093 participants, with a representative age distribution, were divided into two groups of 548 and 545 people. Both groups saw the same job ad; for one group it contained no seal, for the other the “Top Arbeitgeber” employer seal. Participants rated on a scale from 0 to 10 how likely they were to apply. Ratings of 8 to 10 were counted as likely, low ratings as unlikely.

Because the job ads were otherwise identical, the difference between the groups can be attributed to the seal. The experiment was preceded by PhDr. Oliver Scharfenberg’s doctoral dissertation, a market analysis of more than 60 employer seals in Germany.

The research discloses one connection: the seal tested in the experiment was the “Top Arbeitgeber” seal of the Deutsches Institut für Qualitätsstandards und -prüfung (DIQP), and Oliver Scharfenberg acts as scientific advisor to the DIQP. We state this openly, as he does in his books.

To make the results verifiable, the method, sample sizes and results are published on ResearchGate. The central finding, that seals work when they are based on transparent criteria and real employee surveys, is consistent with the wider research literature on quality signals, which the study reviews.

Please cite the original publication with author, year, title and source. For example:

• Scharfenberg, O. (2025). Effect of employer seals on potential applicants: How do seals of quality work and how have applicants’ requirements changed in recent years. ResearchGate.
• Scharfenberg, O. (2026). Mitarbeitergewinnung für kleine und mittelständische Unternehmen: Grundlagenwissen zur erfolgreichen Besetzung Ihrer Stellenangebote. Dubai: self-published. ISBN 978-3-9826678-3-6.
• Scharfenberg, O. (2024). Marktanalyse bestehender Gütesiegel für Arbeitgeber in Deutschland: Eine Einordnung nach Vergabeverfahren und Messung des Einflusses von Arbeitgebersiegeln auf das Bewerberverhalten [Doctoral dissertation, DTI University].
• Scharfenberg, O. (2026). The AI visibility SEO & GEO playbook: Building AI visibility with search engine optimization (SEO) & generative engine optimization (GEO).

When quoting figures, please give the exact values, for example 37.96% and 53.95%, and link to the source.

Yes, that is the subject of a separate article. “Impact of Seals of Quality on Consumer Behavior”, published in December 2024 in the International Journal of Progressive Research in Engineering Management and Science, examines how seals of quality affect customers’ willingness to pay when shopping online.

The underlying mechanism is the same as for employers: a seal closes the information gap between provider and customer, and it works best when it comes from an independent body with transparent criteria.

Yes, Oliver Scharfenberg is available for interviews, expert comments and talks on employer seals, employer branding, recruiting and AI visibility, in English or German. Researchers who would like to discuss the method or build on the data are also welcome to get in touch.

Please send your request with a short description of the topic and your deadline to hello@syn.thailandviptravels.com.