Anchoring was first discovered by Tversky and Kahneman (1974) almost 50 years ago and describes the phenomenon that an irrelevant numeric value (anchor) influences a subsequent numerical estimate. Whereas the anchoring effect has been replicated extensively, influences on anchoring are still often unclear and inconclusive. This project investigates the role of expertise on anchoring. Even though being extensively researched in the past almost 50 years, there is still no comprehensive theory of anchoring that reliably predicts the most important aspects of the phenomenon. Moreover, the role of expertise of the estimating individual is still unclear with some research showing reduced anchoring in experts whereas other research finds stronger anchoring effects or at least similar anchoring effects in experts and novices. Both research gaps are addressed in this project. To this end, a paradigm is implemented that allows to manipulate individuals’ expertise. Moreover, anchor relevance and anchor extremeness are manipulated. With this design it is not only possible to examine the role of expertise in anchoring but also to disentangle different anchoring theories making different predictions for these variables. First results show that expertise indeed reduced anchoring. Moreover, relevant compared to irrelevant anchors and extreme compared to moderate anchors lead to larger anchoring effects.