According to students, respectful behavior with students, organizing the subject of teaching in personal projects and programs and explaining the content in a clear and expressive voice were the first, second and third most important indices of teacher evaluation, respectively. The results of chi-square test for Friedman ranking of evaluation indices from students' perspective indicated a statistically significant difference (p=0.0001). Based on the teachers' views, providing clear and understandable explanations, the ability to motivate students to learn and study more and mastery over scientific concepts and curriculum were ranked first to third, respectively. The evaluation criteria differed significantly from the teachers’ point of view according to the results of Friedman test (P=0.045).
Overall, organizing the subject of teaching in a personal plan and program, mastery over the scientific concepts and curriculum and explaining the content in a clear and expressive voice were ranked as first to third most important indices of teacher evaluation according to both students and teachers, respectively (Table 3). The rank of evaluation criteria differed significantly between the point of view of teachers and students (P=0.0001). The employment status of teachers had no significant association with the most effective evaluation target group and the most appropriate evaluation time. There were significant relationships between the students’ field of study and evaluation criteria ranks, expect for midwifery and occupational health students.
Discussion
According to our results, students believe that teachers' personal and communication skills are the most important indices of teacher evaluation. However, the teachers' ability to present scientific content using new teaching techniques and in a clear and expressive voice while providing understandable explanations were also reported as other important indices of teacher evaluation. The results indicated no significant association between teachers’ employment type and evaluation indices. There were statistically significant differences between the indices selected by students in different fields, which indicates the need for designing specific evaluation forms for different educational groups. According to teachers with different employment types, elite students were the most effective target group for teacher evaluation, while general students were the most appropriate group for teacher evaluation according to students. However, both teachers and students believed that the best time for teacher evaluation are at the beginning, in the middle and at the end of each semester.
Based on the results, both teachers and students identified mastery of the subject and having knowledge and experience as the highest-priority teaching skills. They also emphasized on the power of expression and transmission of content in terms of individual characteristics. In general, mastery of content and subject was considered as one of the most important characteristics of a teacher.. According to Gillespie, the lack of mastery over the content was a factor that decreased self-confidence in teachers, and the teachers' knowledge and experience in teaching were the most important characteristics (20). Previous studies in Iran also reported similar findings (21-24). Mastery over the content was reported as the most important characteristic of a teacher in studies of Mobaraki (22) and Ghorbani (25). In addition, Sharifi et al. reported mastery over the content as the second most important criterion of an ideal teacher (21). Ghadami et al. considered the power of expression and transfer of the content by teachers as an important feature (26). It should be noted that mastery over content is not the sole indicator of an ideal teacher, and teachers should be able to transfer their knowledge in an understandable manner (18). Teacher should also be capable of conducting research and become familiar with new teaching methods (24).
According to students, one of the most important communication skills was respect for students, which is a basic human need from Maslow's point of view (25). In the teaching process, respecting learners can facilitate achieving learning goals. Similar to our findings, previous studies found that students expect teachers' behavior to be respectful (18, 25, 26). Another study also emphasized on the importance of mutual respect for promoting communication. In the mentioned study, one of the criteria raised by half of the students was the availability of a teacher for counseling and guidance, which is neglected in the education system. Communicating with the teacher increases student's confidence and learning motivation. Younger students expect their teachers to have a supportive and guiding role and be able to provide solution to their problems (20).
In the present study, the most important criteria of teacher evaluation were teaching and evaluation skills from the teachers' perspective and communication skills and personal characteristics from the students' perspective. In general, factors such as popularity of teachers among students, administrative and executive positions, teaching methods, teacher's strictness and observance of educational rules and regulations by the teacher affect the students' evaluation. Nevertheless, it is also important to pay attention to what the students did not mention as a very important priority.. For instance, asking students for research assignments in the evaluation skills section and giving students responsibility for some of the lessons in the teaching skills section were considered as the least important indices of teacher evaluation. Perhaps the importance of the teachers' evaluation skills from the students' point of view is related to the quality of the final exam questions and grading. However, the concept of this field has been presented in a completely different way from the scientific point of view and from the point of view of professors in the evaluation form (21).

 According to the findings of the present study, it is suggested to first assign coefficient to each priority and then calculate evaluation scores for a more realistic evaluation process. Other evaluation methods such as self-evaluation, evaluation by colleagues, evaluation by group manager and evaluation by elite students should be utilized for a more comprehensive evaluation of the teacher's performance. It is also suggested to measure the validity and reliability of the teacher evaluation tools using a qualitative method and to design evaluation forms according to the opinions of teachers and students in different disciplines. Performing teacher evaluation on a permanent basis according to scientific standards not only strengthen teaching and eliminate weaknesses, but also improve educational decision making and planning.