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Single service plan probe response

Codes and Frequencies

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For all persons, SSPROB reports if the person reported any single service coverage after a probe question was asked to verify whether respondent had any single service coverage.

In 2004, this probe question was added to the survey to increase the accuracy of obtaining information on the prevalence of single service coverage. First, persons were asked what kind of health insurance they had and shown a flash card which listed different types of insurance coverage. Respondents could pick more than one type of insurance and interviewers were instructed to mark all that applied.

Data Collection and IPUMS NHIS Editing Process 

Interviewers first asked, "Are you covered by health insurance or some other kind of health care plan?" Respondents were instructed to "Include health insurance obtained through employment or purchased directly as well as government programs like Medicare and Medicaid that provide medical care or help pay medical bills." Individuals who had answered affirmatively were asked, "What kind of health insurance or health care coverage do you have?" Respondents selected the appropriate response from a card listing various types of insurance coverage:

  • Private health insurance (2004 forward)
  • Private health insurance plan from employer or workplace (1997-2003)
  • Private health insurance plan purchased directly (1997-2003)
  • Private health insurance plan through a State or local government program or community program (1998-2003)
  • Medicare (1997 forward)
  • Medi-Gap (1997 forward)
  • Medicaid (1997 forward)
  • CHIP (Children's Health Insurance Program) (1999 forward)
  • Military Health Care/VA (1997-2003)
  • Military Health Care (CHAMPUS/TRICARE/CHAMP-VA) (1997 forward)
  • Indian Health Service (1997 forward)
  • State-sponsored health plan (1997 forward)
  • Other government program (1997 forward)
  • Single Service Plan (e.g., dental, vision, prescriptions) (1999 forward)
  • No coverage of any type (2000 forward)

In 2004 and the first two quarters of 2005, only persons who did not answer "Single Service Plan" when asked about insurance coverage (HISINGLE) were asked the probe question about having additional single service coverage. However, beginning in quarter 3 of 2005, persons who reported single service plans in the initially health insurance coverage question were automatically assigned as responding "yes" to SSPROB. To increase consistency over time, IPUMS NHIS has recategorized persons who report having single service coverage (HISINGLE) in the initial health insurance question, as responding "yes" to SSPROB in 2004 and first two quarters of 2005. Additionally, in all years, IPUMS NHIS has recategorized the limited number of "unknown-not ascertained" responses to HISINGLE as also being "unknown-not ascertained" in SSPROB, rather than categorizing them as out of universe.


IPUMS NHIS staff recategorized persons who report having single service coverage (HISINGLE) in the initial health insurance question, as responding "yes" to SSPROB in 2004 and first two quarters of 2005; this replicates the NCHS editing procedure implemented in quarter 3 of 2005. This modification increases the comparability of the variable over time, though data users may wish to note that the 2004 and quarters 1 and 2 of 2005 edits were performed by IPUMS NHIS, rather than NCHS.


  • 2004-2018: All persons


  • 2004-2018