How does group size influence dosage in school-based speech sound therapy sessions?

Kelly Farquharson, Florida State University, USA (
Autumn McIlraith, Texas State Education Agency, USA, (
Sherine Tambyraja, Ohio State University, USA (
Christopher Constantino, Florida State University, USA (
Caitlin Fechtel, Florida State University, USA (
Shay Fitzgerald, Florida State University, USA (

Background: Speech-language pathologists (SLPs) provide speech therapy to children of all ages, but treatment is often most effective when provided in early childhood.  However, there are many variables that contribute to that effectiveness, such as the size of group a child is seen in, the frequency and duration of the therapy sessions, and the dosage within the session itself. Dosage is defined as the number of teaching episodes/ opportunities in one therapy session and has been reported as an “active ingredient” that yields change. Empirical studies of speech sound treatment studies report dosage ranging from 14-240 trials per session.  Most research recommends achieving at least 100 trials per session. However, this does not take into account the myriad of constraints placed upon school-based SLPs in the US. Specifically, due to large caseloads, SLPs often see children in groups, which may impact the extent to which 100 trials can be achieved for a child.  

Aim: The current study examined the extent to which group size influences dosage in school-based speech sound treatment sessions using the experience sampling method, in which data were collected in real time during a normal workweek.

Method: This study included a sample of 90 school-based SLPs from 42 different states.  Clinicians were providing treatment to children from preschool through high school. The majority of sessions included children from preschool to 3rd grade (ages 4-8).  This project included two phases.  In phase 1, SLPs completed a 20-25 minute demographic questionnaire that included information on their geographic location, practice patterns, and job satisfaction.  In phase 2, the same SLPs participated in a series of brief surveys every day for one work week using a phone application, The Personal Analytics Companion (PACO) app.  The PACO app was programmed to randomly alert participants to take a 1-minute survey regarding the composition (e.g., group size, dosage, duration) of a recent therapy session. 

Results: Linear mixed models revealed that for every additional child added to a group, dosage for the target child decreased by 13 trials.  Descriptive results show that the number of trials in school-based speech sound therapy sessions ranged from 1-525.  The average number of trials was 51 with a median of 40.  The average session length was 25 minutes (range of 1-60; median 30). Average session frequency was 2 times per week (range 1-5; median 2).  The average therapy session included 2 children (range 1-12; median 2).  When there was at least one other child in the group, that other child was also working on speech sound production only 50% of the time.

Conclusions: Group size negatively influences the dosage of speech sound therapy.  This may result in protracted improvements in speech sound production and longer time in therapy.

Implications for children: You will get more opportunities to practice your speech sounds if you are in a smaller group of friends.

Implications for families: Your child will likely receive more opportunities to practice, and subsequently improve their speech sound production, if they are seen in a smaller group at school.

Implications for practitioners: Educators should consider flexible options when working with SLPs to schedule speech therapy sessions.  SLPs should consider smaller groups for speech sound therapy.  Providing more opportunities to practice within sessions may lead to early dismissal from therapy and reduced caseload sizes.

Funding: This project was funded by a Planning Grant from the Council on Research and Creativity at Florida State University (PI: Farquharson).

Key words: professionals’ voices, education, speech sound therapy, speech sound disorders

This presentation relates to the following United Nations Sustainable Development Goals: