Teacher Coaching: What We Know
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“Teacher coaching has emerged as a promising alternative to traditional models of professional development.” In Kraft, Blazar, and Hogan’s newly updated review “The Effect of Teacher Coaching on Instruction and Achievement: A Meta-Analysis of the Causal Evidence,” they highlight that reviews of the literature on teacher professional development (i.e., training teachers who are already on the job) highlight a few promising characteristics of effective programs:
Teacher coaching focuses on several of these features. While training sessions may improve teacher knowledge, it may be difficult to translate that new knowledge into practice without further support. Coaching programs seek to provide that. Here’s a working definition of coaching: “We characterize the coaching process as one where instructional experts work with teachers to discuss classroom practice in a way that is (a) individualized – coaching sessions are one-on-one; (b) intensive – coaches and teachers interact at least every couple of weeks; (c) sustained – teachers receive coaching over an extended period of time; (d) context-specific – teachers are coached on their practices within the context of their own classroom; and (e) focused – coaches work with teachers to engage in deliberate practice of specific skills.” Kraft et al. distinguish coaching from mentoring and peer-to-peer feedback. Mentoring is often part of the induction process for new teachers and may focus on a wide range of challenges, and peer-to-peer feedback may function differently from an expert coach helping a teacher to implement a specific set of skills.
What do they find?
They identified 44 studies (all based in the U.S.) with either teacher instructional outcomes or student learning outcomes. All 44 came out from 2006 onward, so this is a young literature. And of those 44, only 2 studies had a sample of more than 300 teachers; 19 studies had 100+ teachers. Almost all (91 percent) combined coaching with some other element of teacher professional development, whether group training or instructional materials or example videos of high-quality instruction. On average, they find big improvements in teacher instruction (0.58 standard deviations, although it’s tough to say what a “standard deviation in the quality of teacher instruction” really means), and more modest improvements in student learning (0.15 standard deviations). As you can see in the figure below, the distribution of outcomes varied a great deal across studies. They don’t find any significant differences in outcomes based on program characteristics (e.g., virtual versus in-person), but the sample size is small for identifying those effects, so I’d put that in the “insufficient data” category. But they do find relatively precise zeros on total hours of coaching and on total hours of professional development (when coaching is combined with other things). As the authors note, “the quality and focus of coaching may be more important than the actual number of contact hours.”
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Source: Kraft et al. 2017.
They do a number of robustness checks (for study design and for publication bias, for example); the story remains the same.
Does instruction actually matter?
Since the authors look at coaching interventions and their impact on both instruction and on learning, they can then check whether the quality of instruction seems to be linked to learning. They only have 11 studies, but they see a strong relationship. “Using a simple linear regression framework, we estimate that a 1 SD change in instruction is associated with a .33 SD change in achievement (p = .07).” Phew! That’s not a surprising finding, but it’s a reassuring one.
What about when you go to scale?
They divide their sample into larger programs (100+ teachers) and smaller programs (less than 100). Most of the smaller programs actually had 50 or fewer teachers. The impact on instructional quality is 1.5 times higher for smaller programs, and the impact on student learning is twice as high for smaller programs; check out the figures below. So going to scale is – unsurprisingly – a challenge.
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Source: Kraft et al. 2017.
The authors highlight that one major challenge is finding sufficient coaches! Using highly effective teachers as coaches has the downside that they themselves are teaching less. Virtual coaching could help by reducing travel time. One coaching program for pre-school teachers found similar effects for on-site delivery versus remote delivery, but clearly (1) this requires more study, and (2) many low- and middle-income contexts don’t have sufficiently consistent connectivity to support virtual coaching.
Another challenge is teacher buy-in. Small-scale pilot programs may be carried out in areas with a teaching culture more open to critique. Effectively implementing this kind of program at scale will require growing cultures where teachers accept and seek to incorporate suggestions on how to do better.
The authors provide many helpful recommendations for future research in this area.
What about low- and middle-income environments?
The literature is much smaller outside of high-income countries. Piper and Zuilkowski find positive results of coaching in a study of several hundred schools in Kenya. (A nationally scaled-up version of the program has no comparison group; an initial evaluation shows significant learning happening, but more analysis will be needed to understand how much of that learning is attributable to the program.) A tiny intervention in Thailand had positive impacts on instructional quality. A program in Malawi led teachers to believe they were more competent, but instructional quality didn’t change. And a program in Brazil that used Skype to deliver coaching to 175 schools led to average gains in student learning, with sizeable gains in schools with high-quality implementation.
Take away: Coaching can be an effective way to improve teacher practice and student learning. Implementing it effectively at scale remains a challenge. But there are interesting approaches underway.
- Practice on the job
- Substantive length and intensity of training
- Focus on specific sets of skills
- Active learning
Teacher coaching focuses on several of these features. While training sessions may improve teacher knowledge, it may be difficult to translate that new knowledge into practice without further support. Coaching programs seek to provide that. Here’s a working definition of coaching: “We characterize the coaching process as one where instructional experts work with teachers to discuss classroom practice in a way that is (a) individualized – coaching sessions are one-on-one; (b) intensive – coaches and teachers interact at least every couple of weeks; (c) sustained – teachers receive coaching over an extended period of time; (d) context-specific – teachers are coached on their practices within the context of their own classroom; and (e) focused – coaches work with teachers to engage in deliberate practice of specific skills.” Kraft et al. distinguish coaching from mentoring and peer-to-peer feedback. Mentoring is often part of the induction process for new teachers and may focus on a wide range of challenges, and peer-to-peer feedback may function differently from an expert coach helping a teacher to implement a specific set of skills.
What do they find?
They identified 44 studies (all based in the U.S.) with either teacher instructional outcomes or student learning outcomes. All 44 came out from 2006 onward, so this is a young literature. And of those 44, only 2 studies had a sample of more than 300 teachers; 19 studies had 100+ teachers. Almost all (91 percent) combined coaching with some other element of teacher professional development, whether group training or instructional materials or example videos of high-quality instruction. On average, they find big improvements in teacher instruction (0.58 standard deviations, although it’s tough to say what a “standard deviation in the quality of teacher instruction” really means), and more modest improvements in student learning (0.15 standard deviations). As you can see in the figure below, the distribution of outcomes varied a great deal across studies. They don’t find any significant differences in outcomes based on program characteristics (e.g., virtual versus in-person), but the sample size is small for identifying those effects, so I’d put that in the “insufficient data” category. But they do find relatively precise zeros on total hours of coaching and on total hours of professional development (when coaching is combined with other things). As the authors note, “the quality and focus of coaching may be more important than the actual number of contact hours.”

Source: Kraft et al. 2017.
They do a number of robustness checks (for study design and for publication bias, for example); the story remains the same.
Does instruction actually matter?
Since the authors look at coaching interventions and their impact on both instruction and on learning, they can then check whether the quality of instruction seems to be linked to learning. They only have 11 studies, but they see a strong relationship. “Using a simple linear regression framework, we estimate that a 1 SD change in instruction is associated with a .33 SD change in achievement (p = .07).” Phew! That’s not a surprising finding, but it’s a reassuring one.
What about when you go to scale?
They divide their sample into larger programs (100+ teachers) and smaller programs (less than 100). Most of the smaller programs actually had 50 or fewer teachers. The impact on instructional quality is 1.5 times higher for smaller programs, and the impact on student learning is twice as high for smaller programs; check out the figures below. So going to scale is – unsurprisingly – a challenge.

Source: Kraft et al. 2017.
The authors highlight that one major challenge is finding sufficient coaches! Using highly effective teachers as coaches has the downside that they themselves are teaching less. Virtual coaching could help by reducing travel time. One coaching program for pre-school teachers found similar effects for on-site delivery versus remote delivery, but clearly (1) this requires more study, and (2) many low- and middle-income contexts don’t have sufficiently consistent connectivity to support virtual coaching.
Another challenge is teacher buy-in. Small-scale pilot programs may be carried out in areas with a teaching culture more open to critique. Effectively implementing this kind of program at scale will require growing cultures where teachers accept and seek to incorporate suggestions on how to do better.
The authors provide many helpful recommendations for future research in this area.
What about low- and middle-income environments?
The literature is much smaller outside of high-income countries. Piper and Zuilkowski find positive results of coaching in a study of several hundred schools in Kenya. (A nationally scaled-up version of the program has no comparison group; an initial evaluation shows significant learning happening, but more analysis will be needed to understand how much of that learning is attributable to the program.) A tiny intervention in Thailand had positive impacts on instructional quality. A program in Malawi led teachers to believe they were more competent, but instructional quality didn’t change. And a program in Brazil that used Skype to deliver coaching to 175 schools led to average gains in student learning, with sizeable gains in schools with high-quality implementation.
Take away: Coaching can be an effective way to improve teacher practice and student learning. Implementing it effectively at scale remains a challenge. But there are interesting approaches underway.
Hi Dave, not attaching costs to this interventions makes them very unrealistic to improve outcomes in a system . We know coaching works, what we don't know is how to make it affordable for teacher development in large chunks on education systems. In developing counties the other issue is that finding the coaches becomes very hard too! In particular to coach in new pedagogical approaches.
I agree. The lack of costs is a major problem not just here but in much of this kind of work on education evaluation. Some countries are seeking to repurpose school inspectors for this work -- they already have the mandate to visit schools and observe. Obviously that requires some training and I think the evidence is still not there as to whether it will be effective or not.
I strongly agree that coaching is an effective way to improve teacher practice and student learning. Teacher buy-in and finding areas with a teaching culture more open to critique is one thing, more importantly is finding coaches that have good coaching skills and great skill of giving feedback. I am a literacy coach based in Port Elizabeth, South Africa, current working with 36 teachers from three different schools, providing literacy training and ongoing coaching as follow up. I am a big fan of the GROW model in my coaching practice (Coaching for Performance by John Whitmore) and (Flawless Consulting by Peter Block). In the past three years working with the same teachers, I have some incredible growth and most importantly self-belief, of which this is the underlying goal of coaching. In my growth as a coach, I have learnt that coaching requires plenty of practice for it to work effectively. Yes David, you are right taking school inspectors for this will require some great deal of training on coaching skills. A manger and a coach are different but a successful manager is the one with good coaching skills to complement his/her expertise.
Thanks for the useful blog. Its a good addition to a conversation currently doing the rounds in the policy and programme circles in South Africa. Please will you provide the full Brazil study citation.
Thanks for your inquiry. The Brazil study is still a working paper, but that is now available here.
Thanks very interesting blog!
Great article and observations. In my organization (http://ichooselife.global/)we are implementing a 5 year project funded by UKaid and one of the key interventions is teacher coaching. I recently visited one of the project sites and had a chat with the teacher coaches to share their experiences. Whereas there is no question on the impact of teacher coaching on learning outcomes, this was more effective in primary schools than secondary schools. One of the key determining factors cited was the support of the head teacher and the Boards of Management to support the intervention.The issue of cost is however a major hindrance for this to be done on scale.
Very nice blog. Thanks for sharing with us.
Hi Dev,
You r right that coaching is improve the learning outcomes. However in developing countries the difficiency of good quality coaches is a big issue. How can we build the skills and capabilities of these admins?
Effective blog that i received in KTF program, thank u for sharing this vital information to us. Coaching is very important but we need First knowledge and good practices to share it also to others as a result of coaching. How can we coach if we dont have wide range of knowledge and skills. Through this blog, can help us to be potential and well knowledgeable. Thank you.