Sample children were classified as having a disability based on the reported responses to the following variables:

• VDIFAMOUNT reports the amount of trouble with vision

• HRPROBAMT reports the amount of trouble with hearing

• WALKDIFKID1 reports the amount of difficulty walking without equipment

• WALKDIFKID2 reports the amount of difficulty walking with equipment

• WALKDIFKID3 reports the amount of difficulty walking compared to other kids

• PICKUPDIF reports the amount of difficulty picking up small objects

• UNDRSTYOU reports the child's difficulty understanding the respondent

• UNDRSTCHD reports the respondent's difficulty understanding the child

• LEARNDIF reports the amount of difficulty learning things

• PLAYDIF reports the amount of difficulty playing

• HITBITEDIF reports if the child kicks, hits, or bites others

In 2019, functioning and disability measures included on the NHIS questionnaire were modified to align with validated, internationally-comparable disability measures developed by the Washington Group on Disability Statistics (WG). For more information about the WG initiative, other WG functioning and disability measures included on the NHIS questionnaire, and guidance for researchers about how to use the WG measures in analyses, please see our user note on the Washington Group Disability Measures.