Codes and Frequencies
For sample children between the ages of 5 and 17 and, starting in 2019, sample adults who were either enrolled in or attending school (SCHOOLNOW), SLDAYR reports the number of days during the past twelve months that they missed school due to illness or injury.
The Field Representative's Manuals for 2001 forward noted that "number of school days missed" was part of a survey section relating to "the general health status of the child." The documentation for 1997 forward provided interviewers with no definition of "school" and no guidance on what constituted a school loss day due to illness or injury.
The Manuals for 1981 and 1988 provided slightly more guidance when discussing school loss days for children over the past year:
Much clearer directions came from an earlier question, asked for all children age 6 to 16 (in 1981) or age 5 to 17 (in 1988), that had collected information about school loss days during the past two weeks (see SLDAY2WK). The 1981 and 1988 Manual text related to this earlier question supplied formal criteria for defining a "school-loss day" (though this information was not necessarily shared with respondents):
In 1981 and 1988, the question about year-long school loss days was directly preceded by inquiries about school attendance and grade level. Here, in both years, interviewers were directed to count only "regular school." According to the Manuals for 1981 and 1988, if responses indicated that "the child is attending a nonregular school (that is, vocational, trade, or business schools outside the regular school system)," interviewers were directed, "re-ask the question emphasizing that we are interested in regular schools."
The definition of a "regular school" was somewhat different in 1981 and 1988, however. The 1981 Manual directed, "For this section, also consider attendance at nursery school or kindergarten as 'Going to school.'" By contrast, the 1988 Manual asserted, in the same context, "nursery school and preschool are not regular schools."
For 1997 forward, "school" attendance and school loss days due to illness or injury were entirely respondent defined, with no directions provided to interviewers. The related variable about school loss day in the past 2 weeks, SLDAY2WK, was discontinued after 1996 and thus provided no definitions relevant to SLDAYR for 1997 and later years.
In addition to the differences in definitions and directions related to SLDAYR (as specified in the description of the variable), other factors limit the comparability of this variable over time.
The question for 1981 and 1988 asked, "about how many days was [child] absent from school because of illness?" For 1997 forward, the question asked, "about how many days did [child] miss school because of illness or injury?"
Changes in top- and bottom-codes also limit comparability across year.
In 1981 and 1988, answers were top-coded at 98+ school loss days, while for 1997-2017, responses up to 240 days (the legal length of a school year) were allowed. Beginning in 2018, responses were top-coded at 40 days.
In 1981 and 1997 forward, separate response categories (IPUMS NHIS code "995") identify children age 5 to 17 who did not go to school during the preceding 12 months. In 1988, by contrast, children age 5 to 17 who did not go to school are grouped with other "Not in universe" persons, such as children under age 5.
Questionnaire design changes introduced in 2019 limit comparability with earlier years. The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.
- 1981; 1988: Sample persons age 5 to 17.
- 1997-2018: Sample children age 5 to 17.
- 2019-2021: Sample children age 5 to 17 and sample adults age 18+ who are currently enrolled in or attending school (SCHOOLNOW).
- 1981, 1988, 1997-2021
- 1981, 1988, 1997-2021 : SAMPWEIGHT