Early intervention (EI) applies to children of school age or younger who have or are at risk of developing a disability or other special need that may affect their development. The purpose of EI is to provide services to children and their families to lessen the effects of the condition. EI can be remedial or preventive in nature. Children are typically eligible for ongoing EI if they have at least one developmental delay with a 33% impact, or two delays of 25% impact as determined by professional testing. However, the criteria for qualifying for EI programs are established by state and local governments.

EI may focus on the child alone or on the child and the family together. An Individualized Family Service Plan (IFSP) is often formed based on the desired goals of the EIP. However, the EI official must also approve the final terms of each IFSP. Programs may be center-based, home-based, hospital-based, or a combination. Services range from identification (i.e., hospital or school screening and referral services) to diagnostic and direct intervention programs. EI may begin at any time between birth and school age. However, there are many reasons for it to begin as early as possible, principally to enhance the child’s development, to provide support and assistance to the family, and to maximize the child’s and family’s benefit to society.