For the Variable Jntmo(hip pain in in last 30 days), why are 70% of the observations NIU for years 2002-2013?

HEALTH SURVEYS
1

For the Variable Jntmo(hip pain in in last 30 days), why are 70% of the observations NIU for years 2002-2013?

2

Only sample adults were asked the JNTMO question. A sample adult is the one adult (age 18+) per family who was selected at random to answer additional health-related questions. Thus, any person that does not have ASTATFLG=“1:Sample adult, has record” is coded as JNTMO=“0: NIU”.

Keep in mind that analyses using at least one variable that was answered by only sample adults should use SAMPWEIGHT instead of PERWEIGHT when weighting the data.

Hope this helps.