“…In the period this study was conducted, the methodological variety in studies on co-production has been vastly improved, including natural experiments (Jakobsen, 2013), Q-methodology (Van Eijk and Steen, 2014), and large-N surveys (Parrado et al, 2013). However, at the beginning of this study, most research on co-production represented rather static case studies, and still, most studies remain cross-sectional rather than longitudinal.…”