Skip to main content

Size Matters – 4 Questions to Help Set the Best Group Therapy Size

Group therapy is when a small number of people meet under the guidance of a professionally trained therapist to help themselves and one another.

In some facilities group size is determined by economics — assigning numbers of participants to groups in order to maximize statistics for maintaining or increasing access to funds. However, this is not always aligned with the participant’s needs and the agency’s mission. For example, there is compounding research to indicate that keeping the group small, for example with groups of people who have dementia, may actually save money.

Corrections Canada discusses group size in depth on its website. They found very few empirical studies that indicate optimal group size, however practitioners from diverse program areas consistently recommend that groups not exceed 6-8 participants. They go on to suggest that with larger groups, it is important to also carefully monitor facilitators for burn out.

Just like individual therapy, effective group therapy requires personalization, intensity and a level frequency to achieve best outcomes. The following four questions aim to help you decide the optimal group size for your practice and the participants you serve.

1. What do your participants need?

The best group size is critical for giving the therapist the capacity to assess, evaluate, re-evaluate, and adjust the program quickly as required (e.g., when sensing agitation, withdrawal, isolation or heightened behaviours, or for strengthening a significant and positive moment). The therapist’s key indicators for the success is if the participants’ desired goals are being met:

  • Learning with and from other people’s experiences
  • Gaining more understanding of their own patterns of thought and behaviours around others
  • Developing effective communication skills and strategies
  • Feeling like they are not alone
  • Working on shared problems
  • Exploring helpful interventions

Research found that the most effective groups have a common identity and a sense of shared purpose.

2. What interventions will you use?

Small therapy groups (four or less) offer more time to focus on each individual, but slightly larger groups can offer greater diversity, more energy, and more perspectives. Some interventions require a small group for creating deep social bonds that are known to improve outcomes. Larger group sizes can be successful as well, but only when the participants are already well-connected to one another and have low to no cognitive deficit.

3. Is an open or closed group format best for your group?

In open groups, new members can join at any time. In closed groups, all members begin the group at the same time. Our experience indicates that regardless what group style you decide on, groups work best when members experience similar goals and function at similar levels.

When joining an open group, there may be an adjustment period while getting to know the other group attendees, however participants may prefer that to waiting until a suitable closed group is available. Having both options available may be best.

4. In what group size do you feel you can do your best work?

We all have different personalities, skills and styles when facilitating a group. Some of us are better with individual therapy, others have the capacity to engage larger numbers of people. Some group sizes may work well for you in one setting but not in another. You will know you are doing your best work if you:

  • Are not feeling burn out at the end of the group
  • Are witnessing regular, positive feedback from the participants
  • Can easily identify incremental changes being made towards bigger goals
  • Receive unsolicited feedback from other professionals who are noticing a positive difference in your group participants
  • Find that attendance is consistent with the potential to grow

Group therapy is often shown to be as effective as individual therapy and for some even more effective. Group therapy works, but size matters and it is up to each therapist leader to determine the optimum number to meet the needs of their particular group and achieve effective results.