“…It should be noted that the number of responses collected by the survey distributors varies between 7 and 41. Due to this variation in number of responses collected by each survey distributor, unbalanced panel effects may be present across the survey responses (Choo and Oum, 2013;Chow, 2014;Yokomi et al, 2017;Sarwar et al, 2017a;Sarwar et al, 2017b;Asahi and Murakami, 2017;Fountas et al, 2018b;Fountas et al, 2018c;Fountas et al, 2018d;Fountas et al, 2019). Besides, the effect of the explanatory variables may vary across observations due to the presence of unobserved heterogeneity, i.e., the effect of unobserved characteristics on the respondents' opinions (Hainen et al, 2013;Chu, 2014;Anastasopoulos et al, 2017;Fountas and Anastasopoulos, 2017;Mathew et al, 2017;Brueckner and Abreu, 2017;Song et al, 2018).…”