Following Rules

SIPP is a true longitudinal survey that tracks people over time. With few exceptions, original sample members are interviewed every 4 months over the duration of the panel. When original sample members move to new addresses, interviewers attempt to locate them and continue to interview them every 4 months.

The SIPP rules call for following original sample members who move, provided they are not institutionalized, do not live in military barracks, or do not move abroad. Prior to the 1993 Panel, and resuming with the 1996 Panel, original sample members under age 15 who moved were not followed. Thus, data were collected for them in subsequent waves only if they either continued to live with an original sample member 15 years or older or were age 15 by the last day of the reference period in which they moved. With Wave 4 of the 1993 Panel, SIPP began following all children who were in original sampled households (SIPP Quality Profile, 1998, pp. 3.6), including babies born to sample members during the panel.

When original sample members move into households with other individuals not previously in the survey, the new individuals become part of the SIPP sample for as long as they continue to live with an original sample member. Similarly, when new individuals move in with original sample members after the first interview, they too become part of the SIPP sample for as long as they continue to live with an original sample member. If no original sample members live at an address where a previous interview was conducted, SIPP does not collect information from the new occupants of that address.

Figure 2-1 illustrates the following rules in practice.

Figure 2-1. Following Rules

	Demolished address unit — no interview. Vacant address unit — no interview. Five people (mom, dad, son, daughter, and cousin) reside at this address and thus constitute a household. Wave 1 interview conducted for all five people. Son joined Army and is living in barracks. He is not followed because military bases are outside the scope of the SIPP sample. However, a record exists in the Wave 2 interview reflecting proxy responses by another member of the household. Interviewer takes data on the four people who remain at this address.
	Daughter got married; she and husband live with her parents and cousin at time of Wave 3 interview. The husband is interviewed at the same time that others in the house are interviewed. There is no further information taken on the son (who joined the Army and is living in barracks, which is outside the SIPP universe). Daughter and her husband moved to a new address and formed their own household at the time of Wave 4. The interviewer takes data on mom, dad, and cousin in the first household; and daughter and daughter's husband in the second household.
	The cousin, who is over 15^a, moved and now lives with her mother and father, who were not in the sample originally. Therefore, for this Wave 5 interview, the interviewer takes data from seven people (mom and dad in the first household, daughter and daughter's husband in the second household, and cousin, cousin's mother, and cousin's father) in the third household. In Wave 6, there is no change from the previous wave.
	At the time of Wave 7, the interviewer discovers that mom and dad have moved out of their old home. The interviewer locates mom and dad and interviews them at their new address. The daughter and her husband are interviewed at their previous address, as are the cousin and the cousin's parents. Altogether, the interviewer takes data from seven people (mom, dad, daughter, daughter's husband, cousin, cousin's mother, and cousin's father) in three households.
	Mom and dad have separated at the time of Wave 8. Mom is in the same address as in the previous wave, but dad is in a new location; thus they form separate households. Meanwhile, the daughter and husband now have a baby and the cousin's household has remained the same. The interviewer takes data for eight people (mom, dad, daughter, daughter's husband, daughter's baby, cousin, cousin's mother, and cousin's father) in four households.

Interviewers rely on several sources of information to locate movers. At the first interview, the interviewer obtains the name, address, and telephone number of a person who could furnish the new address should the entire household move. If necessary, interviewers may contact neighbors, employers, mail carriers, real estate companies, rental agents, or postal supervisors to locate original sample members who have moved.

If an entire household moves, the interviewer tries to find the original sample members and interview them at their new address(es) if they remain in the locality. If the household relocates into or close to a different PSU, a SIPP interviewer in that area may interview them. For example, if a couple moves from Boston to Seattle, a SIPP interviewer in the Seattle area will likely interview the couple for the remaining waves of their panel. Should the entire household move more than 100 miles away from a SIPP PSU, attempts will be made to interview by telephone. If the household cannot be reached, the sample members will be dropped from the survey. Specifically, they will be treated as Type D noninterviews (Type D noninterviews are discussed in Chapter 2 of the SIPP Users' Guide).

If only some original sample members move, the interviewer completes interviews with all eligible household members at both the original address and the address(es) of those who have moved. If an original sample member leaves a SIPP household and the remaining original sample members cannot provide a new address, the interviewer will try to find the person through the means discussed above. Similar to what happens with a household, if an individual original sample member moves within the United States but more than 100 miles away from a SIPP PSU, a telephone interview will be attempted. When that is not possible, the person is treated as a Type D noninterview.

SIPP does not interview original sample members if they move outside the United States, become members of the military living in barracks, or become institutionalized (e.g., nursing home residents, prison inmates). The Census Bureau attempts to track such individuals, however. Should they return to the noninstitutionalized resident U.S. population, the Census Bureau will resume trying to interview them.¹⁰

Difference Between Movers and Those Who Are Temporarily Away

There is an important difference between a mover and a person who is temporarily away. A mover no longer lives at the sample address. On the other hand, a person is temporarily away if the household is that person's usual place of residence, according to the membership rules given in Table 2-3, and specific living quarters are held for the person to which he or she is free to return at any time. The following two examples may help to illustrate the distinction:

A college student living on campus with a room held at home is still a household member at the sample address. In this case, the interviewer would try to interview that student or obtain a proxy interview with the household reference person. If the hypothetical college student originally lived in New York and, upon graduation, moved to Los Angeles to live on his or her own, the student would be considered to have moved as of the graduation date. The student's new address in Los Angeles would become his or her new household, and, if the student was an original sample member, he or she would be treated in the same way as any other original sample member who moved to the new address.

If a household member is in the hospital following an operation but is expected to come home, that person is still a household member at the original address. If an individual interview is not feasible, the interviewer might do a proxy interview for that person. If, however, the person moved into a nursing home, he or she would not be eligible for a SIPP interview, whether individual or proxy. At each interview, the interviewer asks the status of any primary sample member who entered an institution between Wave 1 and the current wave. If the interviewer learns that the person has returned to the noninstitutionalized population, an interview is attempted.

^a For Waves 4+ of the 1993 Panel only, SIPP followed original sample persons under 15 years old who moved to other households with or without another original SIPP panel member over 15. In all other panel years, SIPP did not follow original sample persons under 15 years old who moved to other households with or without another original SIPP panel member over 15. In this example, therefore, the cousin is followed because she is over 15. In the 1993 Panel, the cousin would have been followed without regard to age. Back

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¹⁰ A member of the armed forces who lives in a barracks is not eligible for an interview; a member of the armed forces who lives elsewhere is eligible.

Sample Design

Organizing Principles

Selection of Sampling Units

Oversampling Principles

Identifying Sample Members

Interview Procedures

Types of Nonresponse
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Page Last Modified: May 9, 2006

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