The research studies presented in this special issue rest on two assumptions: firstly, that limitations in verbal short-term memory and verbal working memory (vSTM/WM) capacity are likely to be related to impairments in syntax, and secondly that this relationship is likely to be causal, with impairments in vSTM/WM causing impairments in syntax. In this commentary article I make two, linked, methodological critiques relevant to these studies. Firstly, vSTM/WM tasks, by definition, use verbal stimuli, and therefore they are unable to measure a STM/WM capacity independently of language. Secondly, the authors make causal claims on the basis of correlational data. I argue therefore that the authors' favoured explanation that impairments in vSTM/WM cause impairments in syntax might not be correct. I conclude that pinning down the relationship between syntax and vSTM/WM in children with developmental disorders is fraught with methodological challenges, and that if the ultimate goal is to devise effective language interventions, then continuing to explore this relationship might not be particularly fruitful.