“…It rose to prominence again in the United States in the 1970s when the instruction dimension of the role of the principal was emphasized (Townsend et al, 2013;Cheng-Yong, 2012;Neumerski, 2013;Purinton 2013, Lai & Cheung, 2013Townsend et al, 2013;Cheng-Yong, 2012;Sofo et al, 2012;Çalik et al, 2012;Ylimaki & Jacobson, 2012Goff et al, 2012Klar, 2012Hallinger & Lee, 2012). From the 1960s onwards, the definitions of this concept ranged from any activity in which the principal engaged in order to improve instruction, to certain types of activities or actions such as classroom observation (Gorton as cited by Gurr et.al, 2006).…”