Cognitive behavioral therapy (CBT) is regarded as the gold standard psychological treatment for many mental health conditions, and it consists of both in-session and between-session therapeutic tasks, called ‘homework’. But how important is homework in achieving good clinical outcomes?

“It’s fundamental,” says Keith Dobson, Professor Emeritus of clinical psychology at the University of Calgary, Canada, and former president of the World Confederation of CBT. “One of the things I’ve always said in training is that what happens in the therapy session is important, but what happens between therapy sessions is more important.” Professor Nikolaos Kazantzis, director of the Cognitive Behavior Therapy Research Unit (CBTRU) in Melbourne and faculty member at the Beck Institute for Cognitive Behavior Therapy in Philadelphia, is unequivocal too: “Homework is not an add-on to therapy. It is the bridge from insight to change – where therapy moves out of the room and into daily life.”

How much does homework help?

Across three meta-analytic reviews, Professor Nikolaos Kazantzis and colleagues have shown a consistent pattern: homework is not a peripheral extra, but a measurable contributor to change.

The team’s first meta-analysis, published in 2000 in Clinical Psychology: Science and Practice (CPSP), found both a positive causal effect for adding homework to therapy and a positive relationship between homework completion and outcome. Their 2010 replication and extension published in CPSP strengthened that conclusion: therapy conditions with homework produced larger pre–post gains than conditions without homework. In the most conservative comparison, for studies holding the therapy constant and varying only the homework, the advantage translated to roughly 62% of patients improving with homework compared to 38% without it. The team’s 2016 meta-analysis published in Behavior Therapy moved the question on from whether homework matters to how it matters, showing that both the amount completed and the quality of the client’s engagement were associated with outcomes at post-treatment and follow-up, with engagement quality appearing particularly relevant to sustained gains.

Professor Dobson, another CBTRU collaborator, elaborates: “I think that one thing the meta-analyses tell us is that being in a therapy relationship, having someone to talk to, thinking about your problems and just trying to live life differently/better, even if not part of formal ‘homework’, often has a benefit. The difference between doing homework and not doing homework in CBT is important, however, and homework boosts the efficacy of treatment.”

What makes homework effective?

The problem is that clients don’t always do their homework, and when they do, it’s not always done effectively.

One of the most common reasons for this, explains Professor Kazantzis, is that the homework is not personalised enough: “Homework can be technically sound yet clinically ineffective if it is poorly matched to the individual sitting in front of you. Two clients with similar presentations may require very different homework tasks: a reflective client may engage with written monitoring, whereas a more action-oriented client may respond better to behavioural experiments or in vivo (real life) practice.”

Professors Dobson and Kazantzis’ studies support the comprehensive protocol for facilitating engagement with therapeutic homework that Kazantzis first set out in the clinician guide Using Homework Assignments in Cognitive Behavior Therapy (Routledge, 2005, with a second edition pending in 2027). There is evidence from CBTRU research to support the perspective that therapist skill in integrating homework is not a stylistic preference, but a measurable predictor of outcome: in studies of adults (Yew et al., 2021) and young people (Hildebrand-Burke et al., 2024) with depression, greater therapist competence in homework integration significantly predicted better outcomes. For clinicians, this positions homework not as an adjunct skill, but as a core therapeutic competency. It is crucial for clinicians not just to understand why homework matters, but also to know exactly how to design, tailor, and troubleshoot it in everyday practice.

Additional research from Professor Frank Dattilio (Dattilio et al., 2011; Kazantzis et al., 2023), a CBTRU collaborator at the University of Pennsylvania Perelman School of Medicine and Harvard Medical School, along with an earlier US National Survey by Professor Kazantzis published in the Journal of Consulting and Clinical Psychology in 2005, demonstrates that using homework is influenced by therapist beliefs and that those aware of the evidence base tend to use homework.

There can also be a mismatch between what the client wants to change in their life and what the therapist believes is the issue, says Professor Dobson. “For example, the client may see a specific interpersonal problem and conceptualize it as a behavioral issue or a skills issue, whereas the therapist may see it as something about their core beliefs or the way that they think about themselves in general. You have to make sure that the homework is a collaborative exercise and that the client understands what the homework is about. I always ask the client: ‘What do you understand about what you’re going to do and why? What’s the purpose?’.”

What may initially appear as emotional avoidance can be clinically informative: in Professor Kazantzis’s view, it often signals a mismatch between the formulation (case conceptualization) and the task. “The key issue is whether the task appropriately activates the relevant thoughts and emotions, and whether it does so in a way that supports meaningful progress toward the client’s goals. Low engagement is not simply non-compliance – it is clinical data. It can be a clue that the task, timing, or scaffolding is wrong.”

Therapists need to be mindful of the client’s context when setting tasks, too. “Daily realities matter,” he stresses. “Even a well-conceived task will fail if it does not fit into the client’s actual day.”

It’s something Dr Katie McDonnell, a clinical psychologist at University College London Hospital, recognises with some of her teenage clients, who will do an exposure task “just because they’re in that setting by chance rather than intentionally”. She notes: “I think with exposure it’s about being realistic about what they’re going to be able to do and what’s really going to put them out of their way.” Designing exposures for places the client already goes can help ensure they get done: “It’s part of their routine already – but you’re getting them to tweak and change what they do, so they’re bringing up some of that uncomfortable feeling, learning something new.”

Setting expectations

It’s also vital to set out at the beginning of CBT just how important homework is, she says, because some clients – especially teenagers – won’t realise they need to put the effort in outside of the treatment room.

“I think there is something about young people just wanting a quick fix, that all the work will happen in the sessions,” she said. This mentality of “someone will do this for me, someone will sort this out for me” can sometimes be an issue with parents as well. Sometimes, she notes, it’s the parents that need to do the reading and actually carry out the steps for the exposure work outside of sessions before you will see the changes.

Therapists can be to blame too, sometimes holding back from setting homework out of fear of being ‘dictatorial’. Professor Dobson elaborates: “These therapists are often warm and supportive, but do not want to be seen as controlling or putting demands on the client. They may think that it is better if clients solve these problems themselves and so they resist giving suggestions or directions. Unfortunately, if the client has already had trouble solving their problems, this strategy of not being directive can lead to ongoing problems and lack of change, which in turn can lead to frustration from the client and potentially even dropout.”

Homework and the therapeutic alliance

Professor Dobson advises setting homework right from the beginning of the treatment program:“It’s essential to give some homework, even if it’s relatively minor, in the first session.”

Studies by Professor Rob DeRubeis and colleagues at the University of Pennsylvania have found that while a “modest” therapeutic alliance is needed to help the client engage with the homework, homework completion then really helps strengthen the alliance. Professor Dobson notes that when the client and therapist are working together to solve the problem, it helps them to feel like a team, and that they are being successful together.

But he warns that it’s important to make sure this early homework is “appropriate for the stage of therapy; that it’s not too detailed or doesn’t presume to know more than you actually do.” Some therapists – especially junior ones – can lack creativity or skill: “You need to not just be able to assign homework in general, but you need to be able to titrate it and do the appropriate homework for the particular client at that particular time.”

There can be too much homework. Professor Dobson says: “I’ve seen some clients – if they have certain characteristics: they want to please you as their therapist (for example), or they’re perfectionistic themselves – it can definitely be possible to assign too much homework, and to have the client become overwhelmed by it.

Signs of this can include “thought records that are pages long”, he says, “or sometimes they’ll simply stop doing it. They’ll feel overwhelmed and they freeze. So I think it’s up to the therapist to be sensitive to what the client is saying or doing, and to adjust their behavior accordingly.”

Tailoring homework to clients

The tasks must also match the client’s current capabilities. “Homework may require capacities the client has not yet developed, such as identifying thoughts or tolerating distress,” notes Professor Kazantzis. This means it can be important to scaffold the task, rehearse it in session, and build complexity gradually.

Rehearsing in the session also helps with confidence, says Dr Jacqueline Sperling, an assistant professor at Harvard Medical School. “When clients have a chance to practice tasks during sessions and show themselves that they can do them, they may feel more empowered to practice the tasks at home.”

Neurodiversity can add another layer of complexity, says Dr Sperling. Someone with executive functioning difficulties, for example, may be more likely to stick to their homework plan if their therapist teaches them some behavioral strategies first. Coaching them to place reminder notes in frequently passed areas of the home or set alarms with labels in their phones can also help.

Monitoring homework

Phones can come in handy for monitoring homework, too: a 2019 study by Professor Kazantzis (and CBTRU collaborator Dr Judith Callan) found high user appeal and usability for an app that assigned and monitored homework. “There is a clinically useful role for technology when it supports – rather than substitutes for – the therapy relationship,” he says.

The field advanced further in a 2021 special issue of Cognitive Therapy and Research on homework in CBT, when Professor Kazantzis served as guest editor, which focused on engagement, therapist skill, technology-supported practice, and clinical context. As Professor Dobson explored in his contribution to that issue, technology may increase the salience of homework assignments and increase the accountability of clients to themselves and their therapists, although there are interpersonal aspects of CBT that are hard to replicate through technology. In a recent study published in Clinical Psychology & Psychotherapy (Moggia et al., 2026), the CBTRU team showed that psychological effort – the persistence of engagement with homework in the face of challenges or practical obstacles – is a key predictor of symptom reduction when CBT is delivered by mobile app. Professor Dobson concludes: “I think the critical thing is that the method of monitoring is appropriate for the client.”

Take time to discuss homework

Whatever method is used, therapists must set aside enough time at the beginning of sessions to thoroughly debrief the homework. “Like anything, if you don’t reinforce the activity or reinforce the effort it’s going to stop,” Professor Dobson explains.

It’s equally important to allocate plenty of time to plan the next assignments together properly. “I’ve seen therapists get to the end of the session and realize they’re running out of time, so they just ‘throw it out there’ and ask the client to quickly name an assignment. They don’t really talk about what it’s going to be, and that’s where you start to run into troubles,” says Professor Dobson.

Final thoughts

It’s clear that CBT’s effectiveness depends heavily on what clients do between sessions, but it’s not simply a matter of setting tasks and sending them on their way. Homework must be personalized and planned collaboratively with the client: fully discussed before it is agreed to, and fully debriefed afterwards. It should take the stage of treatment into account, as well as the client’s routine and lifestyle.

In 2022, Professor Kazantzis and his Beck Institute for Cognitive Behavior Therapy colleague Dr. Allen Miller set out a comprehensive model that reframed homework as collaboratively supported engagement rather than simple compliance. That model is now being expanded in the second edition of the clinician guide Using Homework in Cognitive Behavior Therapy, currently in preparation and due for release in 2027. The book translates the principles of effective homework into a practical, session-by-session framework that clinicians can implement immediately in routine care.

As Professor Kazantzis concludes: “Effective homework is not about assigning tasks – it is about optimising engagement.”

Professor Kazantzis is delivering a keynote address and full-day pre-congress workshop on collaborative strategies to motivate and tailor CBT assignments at EABCT 2026 in Brussels this September.

References

Dattilio, F. M., Kazantzis, N., Carr, A., & Shinkfield, G. (2011). Therapists’ attitudes towards barriers impeding homework completion in couples and family therapy. Journal of Marital and Family Therapy, 37(2), 121–136. https://doi.org/10.1111/j.1752-0606.2011.00223.x

Hildebrand-Burke, C., Davey, C., Gwini, S., Catania, L., & Kazantzis, N. (2024). Therapist competence, homework engagement, and client characteristics in CBT for youth depression: A study of mediation and moderation in a community-based trial. Psychotherapy research: Journal of the Society for Psychotherapy Research, 34(1), 41–53. https://doi.org/10.1080/10503307.2023.2267166

Kazantzis, N., Dattilio, F. M., Shinkfield, G., & Petrik, A. M. (2023). Clinician experiences of homework in couples and family therapy: A survey of perceived impact on the working alliance. Scandinavian Journal of Psychology, 64(1), 1–9. https://doi.org/10.1111/sjop.12861

Kazantzis, N., Deane, F. P., & Ronan, K. R. (2000). Homework assignments in cognitive and behavioral therapy: A meta-analysis. Clinical Psychology: Science and Practice, 7, 189–202. https://doi.org/10.1093/clipsy.7.2.189

Kazantzis, N., Deane, F. P., Ronan, K. R., & L’Abate, L. (2005). Using homework assignments in cognitive behavior therapy. New York: Routledge.

Kazantzis, N., Lampropoulos, G. K., & Deane, F. P. (2005). A national survey of practicing psychologists' use and attitudes toward homework in psychotherapy. Journal of consulting and clinical psychology, 73(4), 742–748. https://doi.org/10.1037/0022-006X.73.4.742

Kazantzis, N., & Miller, A. R. (2022). A comprehensive model of homework in cognitive behavior therapy. Cognitive Therapy and Research, 46(1), 247–257. https://doi.org/10.1007/s10608-021-10247-z

Kazantzis, N., Whittington, C. J., Zelencich, L., Norton, P. J., Kyrios, M., & Hofmann, S. G. (2016). Quantity and quality of homework compliance: A meta-analysis of relations with outcome in cognitive behavior therapy. Behavior Therapy, 47, 755–772. https://doi.org/10.1016/j.beth.2016.05.002

Moggia, D., Lutz, W., Bakker, D., Schwartz, B., & Kazantzis, N. (2026). Psychometric Evaluation of the Homework Rating Scale—Mobile Application: Reliability and Predictive Validity for Assessing Engagement in Smartphone‐Delivered Cognitive Behavioural Therapy. Clinical Psychology & Psychotherapy, 33(1), e70239.

Yew, R. Y., Dobson, K. S., Zyphur, M., & Kazantzis, N. (2021). Mediators and moderators of homework–outcome relations in CBT for depression: A study of engagement, therapist skill, and client factors. Cognitive Therapy and Research, 45(2), 209–223. https://doi.org/10.1007/s10608-019-10059-2