Numerous studies have attempted to determine factors that condition the IT-enabled productivity of information workers but have not yet arrived at a comprehensive conclusion. A so-called complementarity systems approach has been proposed recently, holding that a number of factors need to be managed in a deliberately synchronized manner in order to generate productivity gains from such workers. However, this proposal does not provide specifications for how such synchronization must be conducted and researched. To remedy this gap, this research conducts two parallel and differently designed studies: a longitudinal quasi-randomized field experiment and a well-controlled online experiment. Regarded jointly, each study offers insights into the investigated phenomenon that the other does not, indicating that both studies complement each other. In particular, these two different research approaches to study the complementarities of productive IT use help us to establish how further research design should be developed to investigate individual productivity when a new, more aligned IT system in a company is used together with complementary factors. Moreover, the results from both studies jointly demonstrate that a mandatory context of IT use might provide better access to individuals with both adaptive and innovative cognitive styles than a voluntary working environment. Finally, both studies demonstrate that more detailed research is needed to understand how the productivity of individuals differs when inappropriate cognitive styles are included in complementarity set-ups. Therefore, the two studies offer new insights into the interplay between the studied factors that condition the productivity of information workers and show the importance of analysing a complex phenomenon with multiple, different, and complementary research designs, as each design has inherent conditions with opportunities and limitations, in order to reveal characteristics about the phenomenon being investigated.