Codes and Frequencies
For sample adults age 18+ who have at least one functional activity limitation (FLANY), and for whom mental retardation was reported as a condition causing any functional activity limitation (FLRET), FLRETMO reports the duration, in months, of the mental retardation.
Data on the duration of limiting mental retardation were collected via the question, "How long have you had [mental retardation]?" Respondents could answer this open-ended question using the time unit of their choice (i.e., days, weeks, months, years, or since birth). The original responses to the question are reported in two complementary variables, FLRETTP (which specifies the time unit) and FLRETNO (which reports the number of such units). For the NHIS public use files, the National Center for Health Statistics (NCHS) recoded the results from these two variables to create two other variables using standard time units: years (FLRETY) and groups of months (FLRETMO).
FLRETMO is completely comparable for 2002-2010.
Beginning in 2011, the phrase "mental retardation" was replaced with the phrase "intellectual disability, also known as mental retardation" in the survey question associated with FLRETMO. Apart from this change in wording, the variable is completely comparable for 2002 forward.
Additionally, there is a change over time in the coding of "unknown" cases for FLRETMO.
All "unknown" cases for this variable share a common first digit of "9." The meaning of the second digit following the 9 differs for 2001 versus 2002 forward. In the earlier period, the "unknowns" were categorized as:
- Unknown number of days (IPUMS NHIS code 91)
- Unknown number of weeks (IHIS code 92)
- Unknown number of months (IHIS code 93)
- Unknown number of years (IHIS code 94)
- Unknown time with condition (IHIS code 95)
In the latter period, "unknowns" were categorized as:
- Unknown-refused (IHIS code 97)
- Unknown-not ascertained (IHIS code 98)
- Unknown-don't know (IHIS code 99)
Analysts can achieve comparability across all years by combining codes with a common first digit of 9 into a single "unknown" category.
- 1997-2013; 2014 2015 2016 2017 2018: Sample adults age 18+ who have difficulty with activities due to intellectual disability, also known as mental retardation.
- 1997-2018 : SAMPWEIGHT