In conjunction with a question about needing but being unable to afford prescription medicine in the past 12 months, the Field Representative's Manual for 1997 defined prescription medicine as "medication which can only be obtained with the approval of a licensed health care professional. The medication is usually obtained through a pharmacy using a written note or telephoned instruction from the health care professional to the pharmacy." In the same context, the Manuals for 1998-2000 provided a similar definition of prescription medicine as "medication which can only be obtained through a doctor or dentist. The medication is usually obtained from a pharmacy or mail order pharmacy using a written note or telephoned instruction from a doctor or dentist." In the Manuals for 2001 forward, the second definition was repeated under the heading "Important Terms" in the section devoted to "Health Care Access and Utilization."

The Manual for 2000 provided a more extensive definition of prescription medicine specifically in conjunction with question for CHNEEDRX3MO:

In 2000 only, the Manual also clarified the meaning of "regularly taken," as follows: "Do not count medicine that the sample child is taking for a short term illness, such as taking antibiotics for 10 days for an infection."

None of these definitions were routinely shared with respondents.