It was described as the "holy grail" of teaching research when it was first published four years ago. And Professor John Hattie's groundbreaking study of what improves pupils' results is still believed to be the biggest and most ambitious analysis of education ever completed.
Visible Learning encompassed the experiences of more than 80 million students across the English-speaking world and took Professor Hattie - then at the University of Auckland in New Zealand - 15 years to complete. After synthesising 815 meta-analyses of education research, Professor Hattie's simple yet startling conclusion was that, out of the 136 classroom interventions identified, the most effective way to improve education was to raise the quality of pupil-teacher interactions. But it seems that, despite the thoroughness of the study, a little more research still needed to be done.
In December, Professor Hattie, now director of the Melbourne Education Research Institute, published an updated version of the league table of classroom interventions. Based on the synthesis of an additional 141 meta- analyses, it added a further 14 interventions to the list. The highest new entry, in fourth place, was a factor not listed in the first study: teacher credibility.
"The key is the students' perception that teachers have credibility in enhancing their learning," says Professor Hattie. "Students are very perceptive about knowing which teachers can make a difference to their learning. And teachers who command this credibility are most likely to make the difference.
"The effects on achievement are high and the reason is that teachers who constantly show students they care, and know about the difference and impact they are having on them, are `visible' and welcomed."
Historically, the notion of credibility has received the most significant attention in the academic field of communication. The first person credited with popularising the idea was Dr James McCroskey, an expert in communication studies who carried out research into credibility in the early 1980s when he was chair of the department of communication studies at West Virginia University.
Dr McCroskey came up with three variables that were widely agreed to be the key factors of credibility: trust, competence and dynamism. A fourth - immediacy - was added by later studies.
In 2000, Dr William Haskins, a professor of speech communication at McKendree University in Illinois, wrote a seminal paper on the subject of teacher credibility (see panel). "Whether at the conscious or unconscious level, a student's perception of the teacher's ethos, or speaker's character, has an important impact on how he or she will react to the teacher and how effective the teacher will be in the classroom," he wrote. "Erosion of a teacher's ethos can quickly spell disaster."
A decade on, Dr Haskins is still in no doubt of the vital role of credibility in educational success. "Perception of credibility is a critical factor in how students and teachers connect with each other," he says.
"Personally, I would rank it as the number one or two influence on student learning. It's certainly in the top 90 per cent of factors because it is really at the core of who we are as educators.
"When I walk into the classroom, all I have going for me is the students' assessment of my credibility. I can have all the latest gadgets and gizmos and techniques, but if the student thinks I'm a jerk, then I'm a jerk."
The first characteristic that a teacher needs to be considered credible is trustworthiness: the pupil must feel the teacher has their best interests at heart and truly cares about their success in class.
Teachers who are consistent and fair with classroom discipline, include all pupils in activities, treat all pupils the same and do not embarrass them are more likely to develop trustworthiness. To develop an even deeper trust, the teacher could ask about pupils' home life and interests outside school.
Dr Haskins believes that trust must be earned through the "pedagogical communication process" that teachers employ with their pupils.
"Any violation of this trust can potentially rupture the professional relationship that teachers need to maintain if honest dialogues are to occur," he says.
Competence is the second key component of credibility. A teacher must not only have mastered their particular subject area, but must also deliver it in a meaningful way. To do this they need good classroom management skills, the ability to answer questions and the capacity to explain complex material in a way pupils can understand.
Teachers must also be dynamic in how they interact with their class and present their material in an exciting and engaging way, using a diverse range of techniques. If a teacher lacks charisma or is unenthusiastic about the topic, they will lose credibility with pupils.
"Teachers need to appear not only in control of their environment, but energised by it," Dr Haskins says: "To look bored or distant invites communication disaster. Such impressions can quickly evaporate any feelings of excitement students have for their teachers or class content."
The most recent addition to the list is immediacy, which involves using certain techniques to reduce distance between teacher and pupils. These can be verbal - for example, using collective pronouns such as "we" or "us", or non-verbal - making eye contact or rearranging the class into a circle so they all feel part of the group.
Dr Haskins' three characteristics of teacher credibility were further promoted in the work of Dr Arletta Knight Fink, former associate director of instructional development at the University of Oklahoma's teaching centre. In the early 2000s, she was engaged in an effort to improve the quality of teaching on campus, specifically student-teacher interaction.
"I was seeing incredibly bright teachers, but they were still having problems with their students," Dr Fink says. "One professor said: `They just don't like me.' This was a man who knew his subject inside and out, but his students were just giving him poor feedback and evaluations. I started thinking about teacher credibility and those three dimensions.
"I interviewed the students one by one and discovered that the students would ask the professor questions in class and sometimes he wanted to give them a good answer, but couldn't compose one on the spot and said he would get back to them.
"The students perceived that as he didn't know what he was talking about. They were seeing him as an incompetent teacher. That was incredibly insightful.
"It made a big difference in his class when he started answering questions on the spot and not worrying about giving perfect answers.
"The second professor we observed was a very shy person and didn't smile a lot, and his students thought he was cold and indifferent and didn't care about them. I told him to start engaging them more in conversation and he started to get to know them better and relax."
Dr Fink wrote a paper on the importance of teacher credibility and began promoting the idea in workshops, conferences and seminars.
"Students simply won't respect the teacher if they don't perceive them as having all three dimensions," she says. "If they are not perceived as competent in their methods or knowledgeable about their subject area, if they are not seen as trustworthy when it comes to giving out grades and marking exams, and if there's no dynamism, then they are bored and switched off and they can't totally engage in the learning experience."
Professor Hattie's latest research, published in his new book Visible Learning for Teachers, suggests that teacher credibility is one of the most important factors in all of learning.
"If a teacher is not perceived as credible, the students just turn off," he says. "If a student doesn't get (the value of education) by the age of 8, they are behind for most of the rest of their school life.
"If you have one bad teacher, there's a higher probability of not completing school. Two or three and it's almost certain."
HOW TO BECOME A MORE CREDIBLE TEACHER
- Adapt messages for listeners by being sincere and honest in the presentation of information.
- Identify strengths and weaknesses in information - for example, reliability and bias - to demonstrate honesty.
- Introduce sources that are trusted by pupils and use them to develop class material.
- Explain the soundness of analysis, arguments and evidence.
- Earn trust by showing trust towards pupils.
- Appear highly organised in the presentation of the subject matter.
- Deliver a message that is as free from errors as possible, including grammar, pronunciation and enunciation.
- Prepare thoroughly by being in control of the subject matter, key issues, sources, evidence, arguments and differing viewpoints.
- Have lesson plans that are organised and detailed.
- Use relevant personal experiences to provide greater insights for students.
- Develop a powerful style of speaking that uses few verbal or vocal hesitancies such as "OK" or "you know".
- Vary physical movements such as gestures, facial expressions and eye contact.
- Vary vocal characteristics, such as rate, pitch, inflection and tone.
- Use a variety of evidence, stories, visual aids and computer programs.
- Have a relaxed body position so that you look comfortable when standing or sitting in front of the class.
- Establish eye contact with the entire class.
- Smile to disarm and relax students.
- Attempt to reduce distance between yourself and students by moving or by moving away from barriers such as desks or lecterns.
Haskins, W. "Ethos and Pedagogical Communication: suggestions for enhancing credibility in the classroom" (2000). Current Issues in Education 3 (4).