This last category, which was first added to the card in 1998, was defined in the Manual for that year as follows:

Single service insurance was first defined in the 1999 Field Representative's Manual as "health insurance coverage paid for by the individual that provides for only one type of service. Examples of SSPs are dental care, vision care, prescriptions, nursing home care, hospice care, accidents, catastrophic care, cancer treatment, AIDS care, and/or hospitalization."

Initially, the NHIS specifically directed respondents to exclude such private single service plans from their reports of private insurance coverage. In 1997-1998, the flashcard listing general types of insurance coverage and handed to respondents stated, "EXCLUDE private plans that only provide extra cash while hospitalized or pay for only one type of service (nursing home care, accidents, or dental care)." From 1999-2018, this policy changed. The category "Single Service Plan (e.g., dental, vision, prescriptions)" was added to the flash card, and the card directed respondents to "INCLUDE those that pay for only one type of service (nursing home care, accidents, or dental care), exclude private plans that only provide extra cash while hospitalized." Beginning in 2019, three separate questions were asked to determine if the respondent had single service plans for dental services, vision services, and prescriptions.

While information on most kinds of single service plans was collected in the survey from 1999 forward, these privately purchased single service health insurance plans were not treated as "private insurance coverage" in HIPRIVATEE. As the Field Representative's Manual for 2001 forward explained, "In trying to determine the appropriate type of health care coverage that an individual has, it is important to remember that for purposes of this survey, Single Service Plans are not considered private health insurance and should not be recorded as such."

The Manual's discussion of COBRA and TCC was as follows:

The categories listed were:

• 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) (1997-2018)

• Military related health care: TRICARE (CHAMPUS)/VA health care/CHAMP-VA (2019 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) (1999-2018)

• No coverage of any type (2000 forward)

Respondents were consistently instructed to exclude private plans that "only provide extra cash while hospitalized." In 1997-1998 respondents were also instructed to "EXCLUDE private plans that ... pay for only one type of service (nursing home care, accidents, or dental care)." Between 1999 and 2018, "Single Service Plan" was added as a possible response, and, consequently, the instructions were changed to read, "INCLUDE those [private plans] that pay for only one type of service (nursing home care, accidents, or dental care)." Beginning in 2019, respondents were asked three separate questions to determine if they had single service plans for dental services, vision services, and/or prescriptions.

In follow-up questions, interviewers recorded the names of up to four private health insurance plans. If the person was reported as covered by CHIP (beginning in 2000), by a state-sponsored health plan, or by another public program (other than Medicaid) that paid for health care, the interviewer recorded the name of that plan. The placement and wording of these questions about the names of specific government health care plans varied across years.

For persons initially reported as not having health care coverage of any kind, interviewers asked whether the person had Medicare coverage, Medicaid coverage, coverage via a Medicaid program or non-Medicaid state-sponsored health insurance program with the appropriate name for the state, CHAMPUS or CHAMPVA coverage, or any private insurance. For those who acknowledged any such coverage, the interviewer repeated the series of questions mentioned above to determine the specific type of coverage.

In addition to HIPRIVATEE, IPUMS NHIS contains other recoded insurance variables.
These are: HIHSE (Covered by Indian Health Service: Recode); HIMILITE (Covered by military health insurance: Recode); HICHIPE (Covered by Children's Health Insurance Program: Recode); HIMCAIDE (Covered by Medicaid: Recode); HIMCAREE (Covered by Medicare: Recode); HISTATEE (Covered by other state-sponsored health plan: Recode); HIOTHGOVE (Covered by other government program: Recode); and HINOTCOVE (No coverage of any type: Recode).