Study designs of evaluations included in the review
Inclusion criteria were not defined in terms of the study design. The included studies appeared to use both diagnostic cohort and case-control designs.
Specific interventions included in the review
Studies that evaluated screening techniques for assessing speech and language delay, which could be applied in a primary care setting in 10 minutes or less by a non-specialist in a primary care setting and used clearly defined measures, were eligible for inclusion. Studies of broader developmental screening instruments were also eligible. A variety of standardised and non-standardised instruments were assessed, many of which were not developed specifically for screening purposes (details were provided). Screening was carried out by parents, medical/doctoral/graduate students, psychologists, speech and language pathologists, research assistants, developmental paediatricians, health visitors, medical practitioners, teachers and paraprofessionals.
Reference standard test against which the new test was compared
Studies that included an acceptable reference standard (not defined) were eligible for inclusion. A variety of reference standards were used across the studies: these included clinical assessment/judgement, specific speech and language screening tools, and batteries of measures (full details were provided).
Participants included in the review
Studies that focused on children aged 5 years or younger and that were applicable to U.S. clinical practice were eligible for inclusion. Studies of children with previously diagnosed conditions known to cause speech and language delay were excluded. The studies were conducted in physicians’ offices, pre-school, speech and hearing clinics, day-care centres, educational and health facilities, or at home. Most of the studies included predominantly white children with similar proportions of boys and girls.
Outcomes assessed in the review
Studies of the accuracy of screening instruments had to report sufficient data to enable the calculation of sensitivity and specificity for outcomes related to speech and language delay.
How were decisions on the relevance of primary studies made?
The authors reported that multiple investigators reviewed the retrieved abstracts, but did not state exactly how many investigators were involved or how any discrepancies were resolved.