Use of risk factors to guide selective screening is not supported by studies. Several aspects of screening have been inadequately studied to determine optimal methods including what instrument to use, what age to screen, and what interval is most useful. Trials of interventions demonstrate improvement in some outcome measures, but conclusions and generalizability are limited. Data are not available addressing other key issues including the effectiveness of screening in primary care settings, role of enhanced surveillance by primary care physicians prior to referral for diagnostic evaluation, non speech and language and long-term benefits of interventions, adverse effects of screening and interventions, and cost.