Under the black-box model, data services do not export (meta)-data describing the conditions in which data are collected, in which they are deployed and processed, and the quality of the data they deliver. Thus, this model creates blind spots that prevent determining to which extent providers can be trusted to use their data services for building target applications. This paper proposes a QoS-based trust evaluation model for black box data services that combines QoS indicators, including service performance and data quality. The paper also introduces DETECT (Data sErvice as a black box Trust Evaluation arChitecTure) which validates our model. The experimental results demonstrate the feasibility and effectiveness of our solution.