Related dichotomous variables indicate whether the child played eight other organized sports, as follows:

• Football (PLAYFOOTB)

• Baseball or Softball (PLAYBASEB)

• Soccer (PLAYSOCCER)

• Rugby (PLAYRUGBY)

• Field or Ice hockey (PLAYHOCKEY)

• Lacrosse (PLAYLACROS)

• Wrestling (PLAYWREST)

• Boxing (PLAYBOX)

For sample children who did karate or judo during the past 12 months, interviewers asked follow-up questions about the frequency with which the child wore protective headgear (HGJUDO) and a mouthguard (MGJUDO) while doing karate or judo. Similar follow-up questions gauged the frequency with which children wore protective headgear and mouthguards while playing the eight other organized sports listed above.

These questions were all part of the sample child health questionnaire in 1991. The 1991 Field Representative's Manual notes that the purpose of such questions was to obtain baseline data on child safety for the "Year 2000 Objectives of the Nation," a series of specific and quantifiable 10-year health objectives set forward by the Department of Health and Human Services in 1990.

In 1998, these questions were part of the "Injury Prevention" section of 1998 sample child "Prevention Module Supplement." The 1998 Field Representative's Manual explains the purpose of this line of questioning as follows: