It Makes a Difference What We Do

In a recently published study, Farquharson et al. demonstrated that individual SLPs, working in the school environment, make a significant contribution to one-year gains in grammar, vocabulary and word decoding: specifically, percentage of variance attributable to the SLP was 11%, 8% and 12% for these three domains respectively. Unfortunately however these researchers were unable to account for these between-SLP differences in effectiveness since years of experience, caseload size and other time pressures did not significantly explain child outcomes.

I have previously described data on phonology treatment outcomes by individual SLP that we reported from a randomized control trial (shown in the table below). These data  similarly indicate that different SLPs achieve different outcomes; in this case, the between SLP effect was observed even when treatment approach and intensity were held constant. You can see that on average children obtained the best outcome in the ME condition (earlier developing stimulable targets) compared to the LL condition (later developing unstimulable targets). However, SLP 4 obtained rather poor outcomes in both conditions and SLP 3 obtained good outcomes in both conditions.Ebert and Kohnert reanalyzed this table and concluded that the SLP accounted for 20% of the variance in outcomes in this study designed to assess the impact of different approaches to target selection.

Rvachew, Nowak 2001 Table 4

So the question is, if experience, time pressure, and intervention decisions do not account for these differences in outcome that are attributable to the SLP, what makes one SLP more effective than another? It is unfortunate that there is no systematic program of research on this question in the SLP field but we can turn to the education literature for clues. Similarly, the vast literature on teacher effectiveness finds that teacher training and years of experience per se do not account for between-teacher differences in classroom outcomes even though teachers have a large impact on their pupils’ learning. More nuanced investigations have found however that teacher competence does explain outcomes in specific domains when measured in terms of specific experience and training. Therefore teachers who have more years of experience teaching first grade, extra formal training in the teaching of reading, and/or demonstrably greater knowledge of literacy concepts can have a significant positive effect on reading outcomes (see Johanson et al, 2015; Piasta et al, 2009).

Despite the regrettable lack of research that definitively identifies the characteristics of effective SLPs, the studies on teacher effectiveness suggest to me that it would be wise to formalize a system of specialisation among speech-language pathologists. Academics have been talking about this for a very long time as I distinctly remember sitting at the “speaker’s table” over thirty years ago during a banquet at which the gentleman seated next to me expounded for a good part of the evening about the need for a formal specialty in fluency disorders. I have forgotten the name of said gentleman who saw no reason to have specialization for phonology! I of course did not agree – phonological disorders, school speech-language pathology, language learning impairments and so on are at least as complex as fluency or dysphagia or aphasia. In any case, in all of these areas of speech-language pathology practice, specialist knowledge of the underlying theory and concentrated experience in the application of that knowledge will improve outcomes for the children and adults that we serve. For some reason the idea has never really taken off in the clinical community but I would be very happy if the certification boards or regulatory bodies would take it up.

Another message that I draw from Farquharson et al.’s interesting study is that it makes a difference what we do! Sometimes we get so weighed down by factors outside our control – excessively large caseloads, administrative interference in treatment choices, increasingly complex cases and so on – that it is easy to forget this. Digressing back to the studies on teacher effectiveness, another variable that comes up frequently is attitude – teachers who believe in their own self efficacy and in their pupils’ capacity for growth get the best outcomes. I am sure that the same is true for SLPs and therefore I repeat the point when I can, it really does make a difference what you do.


Ebert, K., & Kohnert, K. (2010). Common factors in speech-language treatment: An exploratory study of effective clinicians. Journal of Communication Disorders, 43, 133-147.

Farquharson, K., Tambyraja, S., Logan, J., Justice, L. M., & Schmitt, M. B. (2015). Using hierarchical linear modeling to examine how individual SLPs differentially contribute to children’s language and literacy gains in public schools. American Journal of Speech-Language Pathology, 24, 514-516.

Johansson, S., Myrberg, E., & Rosén, M. (2015). Formal teacher competence and its effect on pupil reading achievement. Scandinavian Journal of Educational Research, 59, 564-582.

Piasta, S. B., Connor, C. M., Fishman, B. J., & Morrison, F. J. (2009). Teachers’ Knowledge of Literacy Concepts, Classroom Practices, and Student Reading Growth. Scientific Studies of Reading, 13(3), 224-248.

Rvachew, S., & Nowak, M. (2001). The effect of target selection strategy on sound production learning. Journal of Speech, Language, and Hearing Research, 44, 610-623.

Rvachew, S. (2015). Testing combinations of phonological intervention approaches for francophone children. Behind the Science podcast. CREd Library.