“…Most of the studies on determinants of healthcare expenditure have used demand function approaches to analyse the factors explaining healthcare expenditures, where healthcare expenditures are hypothesized to be a function of income (Newhouse, 1977) and a selection of non‐income variables such as population density (Crivelli et al, 2006; Hosoya, 2014), population's age structure (Barkat, Mrabet, & Alsamara, 2016; Okunade, Karakus, & Okeke, 2004), foreign aid (Barkat et al, 2016; Murthy & Okunade, 2009) and political stability (Biadgilign et al, 2019; Imoughele & Ismaila, 2013). While some models have applied either cross‐section regression (Murthy & Okunade, 2009) or time series regression (Tajudeen, Tajudeen, & Dauda, 2018), most studies have employed panel data models in both developed countries (Baltagi & Moscone, 2010; Murthy & Okunade, 2016) and developing countries (Barkat et al, 2016; Barkat, Sbia, & Maouchi, 2019; Lv & Zhu, 2014).…”