  Empirical sciences and in particular psychology suffer a methodological
crisis due to the non-reproducibility of results, and in rare cases,
questionable research practices. Pre-registered studies and the publication of
raw data sets have emerged as effective countermeasures. However, this approach
represents only a conceptual procedure and may in some cases exacerbate privacy
issues associated with data publications. We establish a novel,
privacy-enhanced workflow for pre-registered studies. We also introduce PeQES,
a corresponding platform that technically enforces the appropriate execution
while at the same time protecting the participants' data from unauthorized use
or data repurposing. Our PeQES prototype proves the overall feasibility of our
privacy-enhanced workflow while introducing only a negligible performance
overhead for data acquisition and data analysis of an actual study. Using
trusted computing mechanisms, PeQES is the first platform to enable
privacy-enhanced studies, to ensure the integrity of study protocols, and to
safeguard the confidentiality of participants' data at the same time.
