Results
The results of our reliability analysis showed that the values of Cronbach’s alpha for the seven dimensions or subscales were .88 for “facilitating the vision,” .93 for “school culture and instructional program,” .91 for “managing the organization,” and .93 for “collaboration and community engagement,” .92 for “ethics and integrity,” .94 for “understanding publics,” and .91
 
for “research methodology.” These high reliabilities indicate that the survey questionnaire consistently reflects the constructs that we intend to measure.
Table 2 compares the means and standard deviations of school principals, EdD program graduates, and university doctoral faculty on the seven dimensions of knowledge, skills and values for effective school leadership. EdD program graduates had higher rates on all the seven dimensions than school principals and doctoral faculty. School principals, on the other hand, had higher rates on the first five dimensions and lower rates on the last two dimensions than doctoral faculty. Overall, the results of MANOVA revealed a significant difference among the school principals, EdD program graduates, and doctoral faculty on the mean importance ratings for the seven dimensions of knowledge, skills, and values, Λ = .860, F(403, 806) = 4.49, p < .001.
The follow-up discriminant analysis showed two discriminant functions. The first function accounted for 87.1% of the variance, canonical R2 = .12, whereas the second accounted for only 12.9%, canonical R2 = .02. In combination these two discriminant functions significantly differentiated the three groups of membership, Λ = 0.14, χ2 (14) = 61.02, p < .001. As shown in Table 3, the first function discriminated school principals from doctoral faculty, with higher scores characterizing “facilitating the vision,” “school culture and instructional program” and “managing the organization,” and lower scores characterizing “understanding publics” and “research.” The second function separated EdD program graduates from school principals and doctoral faculty, with higher scores on all seven dimensions of knowledge, skills, and values. In other words, principals had significantly higher scores on the first three dimensions than faculty, while faculty had significantly higher scores on the last two dimensions than school principals. Among the three groups, EdD program graduates had significantly higher scores on all of the seven dimensions than school principals and university doctoral faculty.
As shown in Table 4, PhD holders had higher rates on the seven dimensions than EdD and Master’s/ professional degree holders, and EdD holders had slightly higher rates on the last two dimensions (“understanding publics” and “research”) than Master’/professional degree holders. However, the results of MANOVA showed a statistically non-significant difference among these three school principal groups on their perceived importance of the knowledge, skills, and values for effective school leadership, Λ = .948, F(317, 634) = 1.22, p = .257, which indicate that the level of principals’ education had no significant effect on their importance ratings of competencies for effective school leadership.