Employer seals can increase applications, but only if they are credible. Research by PhDr. Oliver Scharfenberg, CEO of Syntharis Group, compared more than 60 employer seals and tested their effect in a representative experiment with 1,093 participants. Adding a credible employer seal to a job ad raised the share of people who said they would likely apply from 38% to 54%, a gain of almost 16 percentage points. The share who were unlikely to apply fell from 18% to 6%.

The condition behind that lift is credibility: it appears when a seal rests on transparent criteria and real verification (ideally an anonymous survey of the whole workforce) rather than on payment. In his Praxisleitfaden Mitarbeitergewinnung, Scharfenberg sorts seals into four categories, from representative employee surveys (the gold standard) to seals based only on online reviews. Since 27 September 2026, the EU EmpCo Directive, implemented in Germany through the third amendment to the UWG, prohibits sustainability labels without a transparent certification scheme; whether the same standard applies to employer seals is still an open legal question. Syntharis advises employers on which certifications are worth pursuing and how to communicate them without overstating what they prove.