There are two type of knowledge – tacit ( which is acquired on the job through trail and error and which may be regarded as knowledge gained through practice ) and traditional academic research-based knowledge ( empirical, codified, evidence-informed ). Principals and other leaders have tended to rely heavily on tacit knowledge for various reasons, including the relative weakness of the body of research-based knowledge; in future, it is desirable to integrate both types of knowledge to the benefit of school leaders, thereby enhancing their successful practice