In the pharmaceutical industry, physicians control more than four fifths of health care expenditures, situation leading to a high investment of the pharmaceutical companies in marketing, aiming to influence phsyicians in their prescription behavior. Marketing-related factors influencing prescription behavior include detailing and detailing ceilings are a form of government-imposed regulation on companies’ promotion. Counterfactual simulations made by previous researchers suggest that a detailing ceiling may have a negative effect on drugs sales. Our thesis focuses on the impact of detailing ceilings on physicians’ prescription behavior, contributing to this stream of research. We used a mixed method approach, starting with a quantitative phase using a time series of drug sales and promotion investments (IQVIA). We used four models applied by Leeflang & Wieringa (2010) and applied seven other models to 18 products in four markets. We performed a series break test on detailing elasticities (before and after the ceiling). We then made 20 in-depth interviews with officers from the pharmaceutical market, to understand the quantitative results
