Therapists do not improve with experience alone.

On average, they stagnate or deteriorate. This is a curious phenomenon and we need to understand it. Here is part one of a three part series that aims to do just that.

“Experienced therapist.” It has a certain ring to it. A certain appeal. Almost certainly more appeal than “inexperienced trainee therapist”, if you’re in the market for help. But maybe it shouldn’t. Why? Because therapists are not fine wines that mature over time. They are not hard cheeses. They are not cast iron skillets seasoned by use.

Therapists, in their developmental trajectories, are, on average, more like countryside cottages. The roses climb the walls and bloom. The fancy garden gnomes proliferate. So quaint. So appealing. So cottagey. Yet all the while the plaster cracks and the window frames warp and the damp creeps in and there is a gradual (so gradual as to be barely perceptible but it’s there nonetheless) decline in its performance of the primary functions of a house. But there are so many gnomes….

Research suggests that therapists, on average, do not improve with experience and time, and those with more experience do not perform better than those with less.

When I first came across this, I was astonished. I clutched my head in my hands and I rubbed my eyes and I asked: how the hell does experience not lead to better outcomes?

I had always assumed the relationship was positive and mostly linear, with returns diminishing only gradually over time. I had some kind of innate faith in the ability of human beings to learn from experience simply by having that experience. Every experienced therapist I met sounded so good, and so much better than me. They had so many gnomes in their garden. I had assumed that if I kept practicing (as in doing therapy), I would inevitably keep improving. But therapeutic experience does not necessarily bring improvement, and in many cases it coincides with deterioration.

These findings are so important, because they lay the foundations for understanding how therapist outcomes can deteriorate with accumulated experience, and what can be done to help experience contribute to improvement instead.

In this post, I’ll lay out the research that examines the relationship between experience and outcomes. In the next one, I’ll outline some of the possible reasons why experience can be associated with a deterioration in outcomes. In the third post, I’ll explore some of the things that might help to translate experience into better outcomes.

The effect of therapist experience has long been of interest to researchers. In 1955, Myers and Auld conducted a study examining the psychotherapy outcomes of patients in a psychiatric outpatient clinic, who saw either a resident psychiatrist (less experienced) or a staff psychiatrist (more experienced). The study has tremendous limitations, to the extent the results are barely worth interpreting, but they will be interpreted anyway. The limitations in themselves are quite interesting, and underscore just how far psychotherapy research has come.

This was seemingly before the days of outcome measures, or any attempt to measure outcomes with a veneer of objectivity. Instead, outcomes were determined by looking through therapy notes and inferring an outcome, then categorising it as patient quit/ patient unimproved/ patient improved/ therapy continued elsewhere. For example, the following therapy note was categorised as “patient unimproved”: “In view of the very difficult circumstances in which the patient lives, it seemed that psychotherapy would not have much chance.” The next note earned a “patient improved” label: “I feel she can handle her problems with considerably more freedom than when she came. She seems to have benefited from therapy.”

In this sample of 39 case outcomes across 12 therapists, the authors inferred that the more experienced staff psychiatrists had “more successful terminations and fewer failures than the residents”, suggesting more experienced clinicians attained better outcomes.

However, the authors note, “the differences in the manner of termination between the senior staff and residents may be due to different conceptions of improvement based on differential experience and training”. So there is no sense of a common definition of improvement. Perhaps the more experienced therapists defined improvement more liberally.

The authors offer this beautifully candid caveat:

“We did not make any check on the reliability of our classifications, since it would give a spurious impression of objectivity to study reliability of classification when we have no way of testing the reliability of the raw record.”

I glimpse a flash of red in my garden. I classify it as an orchid, but I don’t look again to double check, because there is absolutely no way of testing whether I might have actually seen a poppy or a dahlia or a ready salted crisp packet pulled from a bin bag by a fox.

There was also something strange going on with case allocation in this service. It seems to be the polar opposite of every service I have ever worked in. In my experience, more senior clinicians take on the seemingly more “challenging” cases, and trainees are allocated seemingly less “complex” cases.

But in this study, the authors write:

“There may also be differences between senior staff and residents in the selection of cases. For instance, it is possible that the senior staff on the basis of clinical experience select cases more likely to be successful and leave the “poor” cases for the residents”.

What a place to train.

As the topic garnered more attention, and was approached with methodologies that offer some impression of objectivity, spurious or not, findings began to coalesce around an absence of improvement with experience.

Minami and colleagues (2009) examined eight years worth of outcome data (measured on the Outcome Questionnaire-45; OQ-45) from a university counselling service. They included data from 2,672 service users seen by 148 different therapists of various orientations, including psychodynamic, cognitive behavioural, interpersonal, humanistic, existential, feminist, and multicultural. These therapists spanned a range of training and qualification levels, which the researchers grouped into “staff” (clinicians who have completed graduate training), “interns” (predoctoral psychology interns or masters of social work/ counselling interns) and “other trainees” (doctoral practicum students on their first clinical placement). The most qualified clinicians (staff) showed inferior effect sizes (d = 0.131 per session¹) compared with the interns (d = 0.208 per session) and other trainees (d = 0.218 per session).

However, assignment was not random. The most complex cases were assigned to staff clinicians, so it is reasonable to hypothesise that at least some of the disparity is accounted for by this imbalance.

However, a similar study by Budge and colleagues (2013) with 1318 patients seen by 64 therapists (modality not specified) found similar results even after controlling for clients’ pre-therapy functioning. The interns/post docs achieved more significant change in terms of life functioning and symptom reduction compared with qualified psychologists, measured with the Behavioral Health Measure. In terms of the well-being subscale, there was no significant difference. Trainees achieved similar, or better outcomes, than qualified psychologists.

A smaller study (282 patients seen by 34 therapists) conducted in a specialist, CBT-focused anxiety disorders service found no overall difference in outcomes between trainees and qualified therapists (Mason et al., 2015), although there was an interaction such that qualified therapists attained significantly better outcomes with more severely anxious patients. Notably, the trainees utilised 2.3 fewer sessions than qualified therapists (10.3 vs 12.6). Both Mason and Budge suggested that the level of supervision received by trainees may have contributed to their favourable outcomes. Mason and colleagues (2015) also highlight the freshness of trainees’ theoretical knowledge.

When I was in training, I used to dread asking service users if they would be willing to work with a trainee. I felt like I was asking them if they would accept an inferior service.

But I was always pleasantly surprised (and relieved) by how many people agreed to see a trainee. I don’t recall anyone declining. I wondered whether I would have been so willing to work with a trainee myself. But it seems the service users were wiser than I was. These studies suggest that it would sometimes perhaps make sense to request a trainee instead of a qualified clinician.

Another study found that greater therapist experience (measured as years working in a specialist mental health service) was associated with reduced recovery odds, and less symptom improvement in anxious youth (Fauskanger Bjaastad et al., 2018).

However, a limitation of the studies described so far is their cross-sectional nature. The therapists grouped together could differ on other variables. They could have substantially different levels of prior experience, for example. Later studies have rectified these limitations with longitudinal designs, in which changes in outcomes can be examined within individual therapists as their experience increases, or as they move through successive stages of training.

Goldberg, Rousmaniere and colleagues (2016) analysed data from 6591 service users seen by 170 therapists (mostly integrated/ eclectic). On average, a therapist’s data spanned 4.73 years. They found that therapist outcomes (on the OQ-45) deteriorated as experience (measured as chronological time or as number of cases) increased. The effects remained even when controlling for a range of therapist, patient and caseload variables. For each additional year of practice, on average, a therapist’s effect size would drop by d = 0.012. That is a very small effect, and would amount to, each year, one fewer successful outcome out of 148 patients seen. Yet, over a large population of therapists, that starts to rack up. There was notable variation between therapists. 39.41% of therapists’ outcomes improved over time, while 60.59% deteriorated. This heterogeneity is substantial at the extremes. Some therapists showed dramatic improvement, and some showed mindboggling deterioration. Understanding what causes these differences is crucial, and will be the topic of the next two posts.

Germer and colleagues (2022) replicated this study in the German healthcare system, and found no significant relationship between therapist experience and therapy outcomes.

Erekson and colleagues (2017) conducted a study with similar longitudinal, within-therapist analyses, but focused on change in outcomes as therapists progressed through different stages of training. They found that the amount, and the rate of change therapists were able to achieve either stayed the same (when both stage of training and cumulative number of cases were included in the model), or deteriorated (when only one of the variables was included).

The authors wrote: “Findings suggest that as therapists progress through formal stages of training, they do not improve in their ability to effect change in their clients.”

They add:

“Although this and other studies have implications for experience in general, our study provides persuasive evidence that completion of training over time does not imply improved client outcomes for individual therapists. This indicates a potentially radical implication of these study results—that existing structures for training psychologists, including formal graduate training, internship, postdoctoral appointments, and licensure, do not appear to be connected to improvement in client outcomes or therapy efficiency.”

In another longitudinal study, Coleman and colleagues (2024) looked at outcomes for 42,690 service users seen by 613 therapists across 12 years. The study broke outcomes down into four domains: general distress, life functioning, anxiety and alcohol/ drug use. Therapist outcomes deteriorated across time in terms of general distress, life functioning and anxiety. There was no significant change in terms of alcohol/ drug use outcomes.

Taken together, these studies present a rather curious picture. Therapists, seemingly, do not improve with experience, and do not even improve with the completion of their training. On average, at a certain point in their training, therapists hit a peak which they don’t progress beyond.

However, there are two notable exceptions in the literature (this does not include Myers and Auld and their honorable decision not to “give a spurious impression of objectivity”). Two merciful exceptions that offer an escape from the kind of bleak picture built up so far. These studies created very specific service contexts geared towards therapist improvement. I’ll talk about them more in part three. But I’ll tell you now–there are no gnomes involved.

1. Cohen’s d effect sizes are described as small (d = 0.2), medium (d = 0.5), and large (d ≥ 0.8)