common factors

According to “common factors theory,” the essence of successful therapy lies in shared core elements, and the differences between therapeutic approaches are often less important than fulfilling these fundamental criteria.


One frequent question people ask themselves when they first decide to seek therapy is, “What type of therapy should I get?”

There are many different types of talk therapy to choose from. Often specific types of therapy are geared toward specific mental disorders. Cognitive-Behavioral Therapy is common for depression and anxiety disorders, Dialectic Behavioral Therapy is common for bipolar and mood disorders, and EMDR is common among those with PTSD.

How much do these therapies differ? How much does it matter?

One interesting idea in psychology is “common factors theory.” The basic premise is that effective therapy isn’t necessarily based on any specific type of therapeutic tool or technique, but rather there are underlying factors behind all therapies that make them successful.

Many therapeutic systems have been invented over the past century. Today, every popular therapist or coach has their own trademarked brand that’s sold as the absolute best approach to mental health.

The less glamorous truth is that most successful therapies aren’t special. There’s significant overlap between different approaches, with a couple extra bells and whistles. However, at the end of the day the biggest reason they are successful is because they all meet fundamental criteria.

Below you’ll learn more about these “common factors” behind successful therapy, including: collaboration, empathy, alliance, positive regard, genuineness, and individual differences.


6 Common Factors Behind All Successful Therapy

One interesting study identified 6 common factors behind all “evidence-based” therapy. They also calculated estimates on how much each factor contributed to the overall variability of therapeutic outcomes.

Here are the 6 common factors behind all successful therapy:

  • Goal consensus / collaboration (11.5%) – The most important factor is that both the therapist and client share the same goal and they’re willing to work together to achieve it. A goal can be anything from managing negative emotions, to stopping bad habits, to improving communication skills. If their goals mismatch (such as the client not wanting to change or the therapist wanting to go in a different direction), then it’ll be difficult if not impossible to make any progress. Both people need to be on the same page.
  • Empathy (9%) – The therapist must have a clear understanding of who their patient is and where they are coming from. This means being aware of their current thoughts and feelings, but also learning a comprehensive history of that patient’s past experiences and background. We build empathy by seeking knowledge and understanding about another person. Don’t try to guess, label, or project where someone is coming from. Ask questions and learn. A therapist must treat each person as their own individual case. A scientific study of n=1. Every person has a unique story and a therapist’s job is to learn each person’s story.
  • Alliance (7.5%) – Both therapist and client must see their relationship as a partnership where each puts in equal effort to realize their shared goal. For the therapist, this means providing advice, encouragement, compliments, and constructive feedback. For the client, this means putting in work outside of the therapy session (in everyday life) so they actually see changes and results. A healthy alliance requires three main components: 1) A shared bond between therapist and client, 2) Agreement about the goals of therapy, and 3) Agreement about the tasks to achieve it (practical advice, tips, suggestions, exercises, homework). Therapy has to be viewed as more than just talking once per week, but rather an impetus to work together, create a plan, and achieve real progress.
  • Positive regard / affirmation (7.3%) – It’s important that the therapist treats the patient with optimism, positivity, compliments, and encouragement. While a therapist sometimes needs to provide critical and constructive feedback, they should generally promote the patient’s self-esteem and core values. If a therapist tries to fundamentally change something about a person that they don’t want to, there’s naturally going to be conflict and difficulties. One idea known as unconditional positive regard was popularized by the humanistic psychologist Carl Rogers. He highlighted the importance of being agreeable and respectful toward the patient’s core beliefs, values, and goals (even if you disagree with them). Rogers saw therapy as a tool to encourage self-discovery and self-awareness, not tell a patient exactly how they should live their life.
  • Congruence / genuineness (5.7%) – Both the therapist and patient need to be open, genuine, and authentic. If the patient feels the therapist is just “putting on an act” or “pretending to be nice,” they are going to want to pullback and disengage from the process. A good therapist needs to be just as vulnerable as the patient. This means sharing relevant thoughts and feelings, being honest and matter-of-fact, and being willing to express emotions when appropriate. One telltale sign of incongruence is when there is a mismatch in body language (including posture, facial expressions, or tone of voice). If a therapist’s words don’t match their body language, the patient likely won’t develop any trust or rapport.
  • Therapist differences (5%) – The last important factor, which may be beyond our control, is personality differences between the therapist and client. Not everyone is designed to get along with everyone, and sometimes the therapist and patient are just too different when it comes to attitude, temperament, background, or lifestyle. Many therapy sessions don’t work out simply because the therapist/patient relationship doesn’t seem to mesh right. This is why it’s recommended that a person tries out multiple therapists when first starting out. Then they can find someone that fits with their personality and a therapist to commit to long-term.

These are the 6 most common factors behind successful therapy. They account for ~50% of the total variability in therapeutic outcomes, so there are still many other factors at play.

In truth, different types of therapies have their advantages and disadvantages, and certain approaches may work better for some and not at all for others.

Regardless of the system, successful therapy often needs to meet the basic requirements listed above. Without these common factors being met, no technique or approach is going to work.


A Warning on Overspecialized Therapy

A therapist needs to be flexible in their approach and try not to force fit everyone into their preferred model.

The more a person is trained and/or educated on a specific field in psychology, the more they seem to be “locked in” to only one way of observing the human condition. They don’t talk to people as human beings at face value, but instead think, “How does this person fit into my cognitive/behavioral/psychodynamic/evolutionary model?”

Expertise (and overspecialization) can narrow vision. A certain element of beginner’s mind is the best approach to therapy. Start with the basic questions, “Who is this person? What do they care about? What makes them tick? What do they want to change?”

Assume nothing and ask questions. Learn about the person from scratch. Connect to them human-to-human and see where it goes.

More concerning, certain therapies have become popularized and over-hyped in recent years. They’ve turned into commercial brands. “Cognitive-behavioral therapy” has become a buzzword in many circles because the average person associates it with the only “evidence-based” therapy.

Of course I’m not against specific therapies. I’ve learned a lot of helpful tools and techniques from various systems (including CBT) that I still practice today.

At the end of the day, I’m a pragmatist, so there’s almost no therapy, treatment, medication, or technique I’m 100% for or against. If it helps just one person, then it’s that much effective.

However, in general, a good therapist needs to have a comprehensive understanding of how humans work. Tools and techniques can be in your back-pocket, but first and foremost you need to approach people as individual human beings seeking growth.

Successful therapy can’t be reduced to a checklist.


The Gloria Tapes: 3 Therapeutic Approaches

This topic reminds me of an old series of videos known as the Gloria Tapes.

It was an educational film made in the 1960s to teach psychology students the differences between therapeutic approaches.

The series follows a single patient, Gloria, who receives therapy from three distinguished psychologists of the time: Carl Rogers, Fritz Perls, and Albert Ellis.

The therapy is limited since it’s only one session each, but you can get a good understanding of the radically different approaches by each therapist.

You can watch each of the sessions here:

Each of these videos reveals a different approach to therapy.

Albert Ellis is most aligned with modern cognitive and rational-based approaches. Carl Rogers has a more gentle and humanistic approach. Fritz Perls has a direct and provocative approach (almost to the point of bullying).

If I remember correctly, the patient Gloria felt the most comfortable with Rogers, but she actually went for a second session with Perls. I don’t know how to interpret that – it’s possible she felt “unfinished business” with Perls or she simply enjoyed arguing with him.

None of this says anything about “successful therapy.” Just one session isn’t adequate to measure “success” vs. “failure” when it comes to a long-term process like self-growth. However, these examples will give you a taste for the different types of therapies out there.

Ultimately, successful therapy depends on both therapist and patient. The most important factor is to have a healthy, working relationship and a “build together” attitude. Once you have that foundation, anything is possible.


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