“…Several studies have illustrated the importance of staff' qualifications for process quality in Canada, the Flemish Community of Belgium, the Netherlands, Portugal and the United States (Barros et al, 2016 [9] ; Bigras et al, 2010 [122] ; Castle et al, 2016 [123] ; Hulpia et al, 2016 [36] ; King et al, 2016 [114] ; NICHD Early Child Care Research Network, 2000 [10] ; Slot et al, 2015 [110] ; Thomason and La Paro, 2009 [6] ; Vogel et al, 2015a [111] ; Vogel et al, 2015b [112] ). Four studies showed positive associations by looking at linear relations between pre-service qualifications and process quality (Barros and Leal, 2011 [90] ; NICHD Early Child Care Research Network, 2000 [10] ; Slot et al, 2015 [110] ; Thomason and La Paro, 2009 [6] ), whereas others showed positive relations from a certain level: either a two-year degree (King et al, 2016 [114] ; Vogel et al, 2015a [111] ) or a Bachelor's degree (Barros et al, 2016 [9] ; Vogel et al, 2015a [111] ). Some studies found associations when using a broad and comprehensive measure for quality assessment including different aspects of staff-child interactions (Barros et al, 2016 [9] ; NICHD Early Child Care Research Network, 2000 [10] ).…”