Panel studies are an efficient research method to gather qualitative data over extended periods of time. Their main purpose is to examine behavioural changes through recurring interviews.The client, Basler Verkehrs- Betriebe (BVB), a Swiss public transport company, has been experiencing customer loss in the last years. For this reason, it wants to initiate a panel study to analyse this problem.

The thesis constitutes a panel concept suitable for the public transportation company. The concept is based on a qualitative study. It includes researching literature on panel studies, the analysis of documents supplied by the client and expert interviews.

The findings suggest a longitudinal panel design, whereby the data is collected through either face-to-face interviews or panel discussions. Through estimations it is concluded that this is the most efficient method, considering the client's resources and capacities. The client mainly benefits from the richness in the data, due to the advantages that face-to-face interviews as well as panel discussions offer. By having invariable panel members, the client achieves efficiency in the maintenance of the panel.