Issues to consider in the evaluation of speech and language therapy for preschool children.

This paper reviews some of the methodological issues involved in the design of a randomized controlled trial currently underway in Bristol. The trial compares the progress of preschool children randomly allocated to a 'watching-waiting' control group with the experimental group who have immediate access to therapy. This paper reviews a number of relevant studies, which have either followed up preschool children with early language delays or have investigated the effects of therapy with this age group. The basic design of the trial is outlined along with a discussion of the sample, the measurements used and the therapy given.