“…One-fifth of the studies used willingness to pay (WTP) measurement methods and applied, for example, conjoint analysis (e.g., Bernard et al, 2018;Fell et al, 2006;Luo et al, 2017;Thompson et al, 2010) and discrete choice experiment (Holopainen et al, 2017;Shoji et al, 2014). Qualitative studies with, for example, focus group discussions (e.g., Häyrinen et al, 2020;Xu et al, 2019) and interviews (e.g., Viholainen et al, 2020) were not popular, even though some of the reviewed studies recognized the need for qualitative methods as well (Roos & Nyrud, 2008a;Toivonen, 2012). However, only four of the studies (Jonsson et al, 2008;Jonsson, 2005;Ridoutt et al, 2002;Xu et al, 2019) used the mixed methods approach with qualitative and quantitative methods.…”