VIG20FNO2 is a variable with three columns and no implied decimal place.
000 = NIU (Not in Universe)
994 = 994+
995 = Never
996 = Unable to do this activity
997 = Unknown-refused
998 = Unknown-not ascertained
999 = Unknown-don't know
VIG20FNO2 reports the frequency, in number of units, with which sample adults in quarters 1 and 2 of 1997 engaged in vigorous leisure-time physical activities for periods of at least 20 minutes. It must be interpreted in conjunction with the variable VIG20FTP2, which reports the time period (e.g., per day, week, month, or year) corresponding to the number of units in VIG20FNO2. For example, a respondent who runs once a day would have a VIG20FNO2 value of 1 (to indicate 1 time) and a VIG20FTP2 value of 2 (which is the IPUMS NHIS code for "day").
VIG20FWK2, a recoded variable created by the staff at the National Center for Health Statistics, draws upon the information in VIG20FNO2 and VIG20FTP2 and reports the frequency of vigorous leisure-time physical activities for at least 20 minutes in terms of a single time unit, times per week.
Vigorous physical activities are described in the survey question itself as activities which "cause heavy sweating or large increases in breathing or heart rate." The Field Representative's Manuals for 1997 forward provide examples of vigorous leisure-time physical activities, although these examples were not routinely provided to respondents. These examples include fast walking, fast bicycling, jogging, strenuous swimming or sports play, vigorous aerobic dance, and strenuous gardening.
Due to an error in the wording of the survey question, VIG20FNO2 is only available for quarters 1 and 2 of 1997. At that time respondents were asked to report how frequently they engaged in physical activities lasting a minimum of 20 minutes. This mistake was corrected beginning in quarter 3 of 1997, when the minimum duration of physical activity was lowered to 10 minutes.
The NHIS Survey Description for 1997 describes this situation of changing reference periods for physical activity as follows:
To allow analysis of vigorous leisure-time physical activity across all quarters of 1997, the National Center for Health Statistics created "transitional" variables for 1997. These transitional variables combined the data on vigorous leisure-time physical activity for at least 20 minutes from quarters 1 and 2, with data from the subset of respondents in quarters 3 and 4 who engaged in vigorous leisure-time physical activity for at least 20 minutes.
In other words, the transitional variables for 1997 allow comparability across all quarters of 1997 only by excluding respondents from quarters 3 and 4 whose physical activity lasted between 10 and 19 minutes (i.e., less than 20 minutes in duration). Researchers who wish to analyze data on vigorous physical activity (for 20+ minutes) for all quarters of 1997 can use these transitional variables:
- VIG20FNO (Frequency of vigorous activity 20+ minutes: Number of units)
- VIG20FTP (Frequency of vigorous activity 20+ minutes: Time period)
- VIG20FWK (Frequency of vigorous activity 20+ minutes: Times per week)
- VIG20DNO (Duration of vigorous activity 20+ minutes: Number of units)
- VIG20DTP (Duration of vigorous activity 20+ minutes: Time period)
- VIG20DMIN (Duration of vigorous activity 20+ minutes: Minutes)
Researchers who wish to analyze data from multiple years on adults' leisure-time vigorous physical activity should restrict their data from 1997 to quarters 3 and 4 and use variables beginning with "VIG10."
See VIG10FNO for an overview of the variables relating to adults' leisure-time physical activity for at least 10 minutes for the third quarter of 1997 forward.
- 1997: Sample adults age 18+ in quarters 1 and 2.
- 1997 : SAMPWEIGHT