Many researchers are interested in knowing if or how much interviewers affect respondent's answers. To enable researchers to investigate these questions all NLSY79 data releases since 1988 have contained information on each interviewer's characteristics. Information on the characteristics of NLSY79 interviewers primarily comes from the National Opinion Research Center's (NORC) interviewer personnel files, which are called ISIS. Data from the 2002, 2004, and 2006 surveys come from forms filled in by each interviewer during their NLSY79 training program.
Most NLSY79 surveys have the following variables available; interviewer ID number, number of times this interviewer has previously interviewed the respondent, the interviewer's race, the interviewer's sex, the interviewer's age, the interviewer's educational level, the amount of time the interviewer has worked at NORC, the languages other than English spoken by the interviewer, a flag identifying if the interviewer was ever terminated and the last known pay rate (in U.S. dollars per hour) for the interviewer. For the surveys run from 1981 to 1985 two additional variables are available; the number of NORC surveys the interviewer worked on during the calendar year and the number of hours spent interviewing during the calendar year. In the 2002 survey one additional variable is available; number of hours spent on the NLSY79 interview project.
Researchers should note that CHRR has built all of these variables from three snap shots of the interviewer characteristics data, plus the surveys filled out prior to the 2002-2006 interview rounds. The primary snapshot reflects interviewer data a few months prior to the fielding of the NLS 1994 survey. Hence, changes in items like an interviewer's educational attainment or pay rate are not reflected in the data.
The key variable, which links the NLSY data set with the ISIS data set is the ISIS Interviewer ID. This variable is similar but not exactly the same as the Interviewer ID variable, which has been found on the NLSY79 public use data set for many years. The ISIS Interviewer ID is constructed from the NLSY79 Interviewer ID variable using the following steps.
First, the NLSY interviewer ID for all years prior to 1996 is divided by ten to truncate the last digit. This last digit was used to cluster interviewers together and the digit was not used in the ISIS database. IDs for 1996 and 1998 do not have this last digit.
Second, each ISIS ID was then run it through the list of all known interviewers who changed their ID. Interviewers changed their ID if they moved to different states, were promoted or demoted. Only a partial list of interviewers who changed their ID is available so there is no year when the characteristics of all interviewers are known. However, even if all the characteristics of an interviewer are not known, every effort was made to create a consistent ID number since a researcher might be interested in knowing who interviewed whom from year to year even if other information like sex is not available.
Third, for all of the surveys after 2002, all NLSY79 interviewers were given new round-specific project ids, whether or not they had previously participated in the project. To match these interviewers, a manual search was done using the interviewers first and last names. If a multiple match was possible because of a common last name (i.e. multiple interviewers with the last name Smith) the birth date was checked to determine a match.
The resulting ID was then used to search the ISIS database. Most of the IDs match but, a small number of Interviewer Ids do not. The following table shows the number and percentage of respondents whose interviewer was found in the ISIS database by survey year. Readers should note that most interviewers interviewed multiple respondents so not finding even a single interviewer in the ISIS database causes dramatic changes in the number and percentage of interviewers found columns.
Two years (1979 and 1987) have large numbers of interviewers who were not found in the ISIS database. 1979 has a large number because the ISIS database was not started until 1980. Any interviewer who worked in 1979 but not in a later year was never added to ISIS. The 1987 interview was primarily fielded via the telephone to save money. Telephone interviewers who did not also do face-to-face interviews are not part of the ISIS database.
Table 1. Interviewers Identified in ISIS by Survey Year
|
Year |
# of Respondents Interviewed |
# of Interviewers Matched in ISIS |
Percentage Not Matched in ISIS |
|
1979 |
12686 |
9619 |
24.2% |
|
1980 |
12141 |
10946 |
9.8% |
|
1981 |
12195 |
10967 |
10.1% |
|
1982 |
12123 |
11400 |
6.0% |
|
1983 |
12221 |
11980 |
2.0% |
|
1984 |
12069 |
11585 |
4.0% |
|
1985 |
10894 |
10374 |
4.8% |
|
1986 |
10655 |
10119 |
5.0% |
|
1987 |
10485 |
6825 |
34.9% |
|
1988 |
10465 |
9394 |
10.2% |
|
1989 |
10605 |
9906 |
6.6% |
|
1990 |
10436 |
9321 |
10.7% |
|
1991 |
9018 |
8105 |
10.1% |
|
1992 |
9016 |
8480 |
5.9% |
|
1993 |
9011 |
8618 |
4.4% |
|
1994 |
8891 |
8701 |
2.1% |
|
1996 |
8636 |
8050 |
6.8% |
|
1998 |
8399 |
7649 |
8.9% |
|
2000 |
8033 |
7814 |
2.7% |
|
2002 |
7726 |
7657 |
0.1% |
|
2004 |
7661 |
6851 |
10.6% |
2006 |
7654 |
6724 |
12.2% |
|
Average |
--- |
--- |
8.4% |
| Note: For 2006 an interviewer was considered to be a match if their age could be determined. | |||
This section describes all the other ISIS variables available beyond the Interviewer's ID.
Interviewer Count
This counts the number of years the interviewer has interviewed the
respondent. For example if the interviewer count in 1986 contains a 4 this means
that the 1986 interviewer for the respondent has already interviewed the person
4 previous times. Please note that the number of times does not include the
1986 interview. Also note the series does not look ahead into the future. If
they are also interviewed by the same interviewer in 1987, this information is
NOT used to calculate the 1986 number. All 1979 values are zero, since no one
has been previously interviewed.
Interviewer Race
1 = WHITE
2 = BLACK
3 = HISPANIC
4 = ASIAN
5 = AMERICAN INDIAN
-3 = missing
Interviewer Sex
1 = MALE
2 = FEMALE
-3 = missing
Interviewer Age
Age of the interviewer in the interview year.
-3 = missing
Interviewer Education
1 = Grade 0-8
2 = Grade 9-11
3 = High School Graduate
4 = Vocational degree
5 = Some College
6 = College Graduate
7 = Graduate School
8 = Masters Degree
9 = Professional Degree
0 = Other
Interviewer Tenure
Number of years spent working at NORC as of interview year.
Interviewer Languages (Not available in 2002 and subsequent data releases)
1 = SPANISH
2 = GERMAN
3 = ITALIAN
4 = POLISH
5 = JAPANESE
6 = CHINESE
7 = YIDDISH
8 = AMERICAN INDIAN
9 = PORTUGESE
Interviewer Type of Termination (Not available in 2002 and subsequent data releases)
0 = Never Left NORC
1 = TERMINATED by NORC for cause
2 = Left NORC by own choice
Interviewer Last Pay Rate at time of ISIS dump. (Not available in 2002 and subsequent data releases)
1 = $3.00 to $5.00 per hour
2 = $5.01 to $7.50
3 = $7.51 to $10.00
4 = $10.01 to $15.00
5 = $15.01 and up
-3 = Pay Rate Not In ISIS
For 1981 to 1985 the following two variables also exist:
Hours
Number of Hours Worked on NORC projects in calendar year
Count
Number of NORC surveys/projects worked on in calendar year
For 2002 the following variable exists.
TotalHours
Hours spent in 2002 on the NLSY79 main, child and young adult surveys.
-3 = missing.