Strange as it might sound to modern-day educators, there was a time in the not too distant past when people questioned the importance of schools and teachers. Specifically, the 1966 report entitled Equality in Educational Opportunity and commonly referred to as the Coleman report in deference to its senior author (Coleman et al., 1966) involved more than 640,000 students in grades 1, 3, 6, 9, and 12 and concludes the following: [Taking all these results together, one implication stands above all: that schools bring little to bear on a child's achievement that is independent of his background and general social context] (p. 235). This was a devastating commentary on the potential (or lack thereof) of schools and teachers to positively influence student achievement. In general, these results were interpreted as strong evidence that schools (and by inference the teachers within them) make little difference in the academic lives of students.
Since then a number of studies have provided evidence for a different conclusion (for a discussion, see Marzano, 2003b). Indeed, those studies demonstrate that effective schools can make a substantial difference in the achievement of students. In the last decade of the 20th century, the picture of what constitutes an effective school became much clearer. Among elements such as a well-articulated curriculum and a safe and orderly environment, the one factor that surfaced as the single most influential component of an effective school is the individual teachers within that school.