| On this page: | On separate pages: Chapter 2 part 1
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Before each survey period began, the Census Bureau generated lists of respondents to be interviewed and distributed them to 12 regional offices. Current addresses and contact information were generated from data collected during the last interview and through a postal check conducted by Census, and cases were assigned to interviewers who lived in the same geographic area as the respondent. Interviewers then received copies of the questionnaire (or a laptop computer for CAPI interviews) and (if used) respondents' Household Record Cards and flashcard and/or information booklets.
In each survey round, interviewers were responsible for contacting each respondent in their caseload and for using additional local level resources to locate those respondents who had moved since the last interview. Respondents who had moved outside the geographic district of their original interviewer were assigned to another unless there are no personnel nearby. In the latter event, an effort was made to interview the respondent by telephone.
Each respondent to be interviewed was sent various materials designed to encourage continued participation. Advance letters thanking respondents for taking part in the interviews and informing them of the coming survey were mailed prior to each interview period. Fact sheets highlighting recent research findings from each cohort's survey data were also provided. Respondents who initially refused to participate in a survey were sent letters and some additional materials by the regional offices designed to encourage their continued participation and were once again contacted by local level interviewers to secure the interview.
While the type of survey, personal or telephone, determined the chief mode of contact, an alternate contact method was used for certain respondents. During a personal survey, for example, those respondents who lived long distances from the Census interviewer's base of operation or those for whom the Census supervisor decided that another contact method was warranted were contacted by telephone. Although survey instruments were written in English only, multilingual interpreters were made available by the regional offices to interviewers who needed them.
Beginning in 1995, respondents in the two women's cohorts were interviewed during the same time period; a single computer-assisted personal interview (CAPI) replaced the paper-and-pencil interview (PAPI) instruments used during the previous interviews. While data were collected simultaneously for the two cohorts, they were released separately by cohort. This CAPI interview continued on a biennial basis through 2003, when the survey ended.
The average length of an interview varied depending on the type conducted, with personal PAPI interviews lasting 50-60 minutes, telephone PAPI interviews averaging 20-25 minutes, and CAPI interviews lasting about 70 minutes. As a validation check, a percentage of the respondents were contacted following the interviews to ascertain that the interviews had taken place. No stipends were paid to Original Cohort respondents for their participation until 2003. During the 2003 fielding a special incentive experiment was conducted to see how a subset of respondents responded to being offered money to participate. Variables associated with this incentive experiment are R65017.00, R76056.00-R76060.00, R76105.10, and R76105.20.
In general, respondents selected for interviewing each year were those who participated in the initial survey and who were alive, residing within the United States at the interview date, and noninstitutionalized. (Exception: In 2003, interviews were conducted with a few institutionalized respondents. See R65097.00-R65124.00.) If a respondent had joined the Armed Forces, she would also have been excluded from interview during her enlistment, but no Mature Women respondents were members of the military during the survey period. However, the criteria used to select the eligible sample--respondents whom the Census Bureau attempts to interview in a given round--have varied somewhat over the years.
Beginning in 1968, any respondent who had refused to be interviewed during a previous round was dropped from the eligible sample. Beginning in 1971, respondents were also dropped from the eligible sample if they had not been interviewed in two consecutive surveys for reasons other than death or refusal (for example, respondents who could not be located or contacted during the field period--those with 'Reason for Noninterview' codes of 1, 2, 3, 4, 5, 6, 8, or 11). In 1982, Census ceased dropping individuals for these two reasons but did not attempt to reinterview those already dropped. For example, a respondent who missed the 1979 and 1981 interviews, or any two consecutive interviews prior to that year, for a reason other than death or refusal was not eligible to participate in 1982 or any subsequent year. Similarly, a respondent who refused to participate in 1981 or any earlier survey was not eligible in 1982 or any later survey. However, respondents who refused to participate or missed their second consecutive interview in 1982 were retained in the sample and were eligible for all subsequent interviews, unless they died, were institutionalized, or obtained a Congressional refusal. The User Notes after Table 2.6.2 describe how dropped respondents can be identified.
Table 2.6.1 below depicts reasons for exclusion from the eligible sample and the years each applied; Tables 2.6.3 and 2.6.4 later in this section present reasons for noninterview across survey years.
| Out-of-Scope Reason | Years Exclusion Reason in Effect |
| Institutionalized | All years. Exception: in 2003, interviewers made attempts to interview respondents in institutions. |
| In the Armed Forces | All years |
| Residing outside the U.S. | All years |
| Deceased | All years |
| Refusal during any one previous interview | 1967-82. If interviewed in 1984, a respondent remained in the eligible sample for subsequent interviews. |
| Dropped due to two consecutive noninterviews for reasons other than refusal, death, or membership in the Armed Forces |
1971-82. If interviewed in 1984, a respondent remained in the eligible sample for subsequent interviews. |
| Congressional Refusal1 | 1984-present |
| 1 Congressional Refusal refers to a congressional representative requesting a respondent not be
contacted again for the NLS after a respondent has completed one or more survey rounds. |
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Each survey year, NLS staff created a cumulative 'Reason for Noninterview' variable for the full sample of respondents. This created variable is a combination of (1) the noninterview reasons provided by Census for the subset of respondents designated as eligible for interview in that survey year and (2) the reason for noninterview assigned during a previous survey to out-of-scope respondents. For several surveys, CHRR released an additional variable reflecting the reasons for noninterview for only those respondents with whom interviews were attempted that year. This type of variable is available in 1974 (R07755.00) and in 1992 (e.g., R10093.00). The number of respondents that Census designated as eligible for interviewing fluctuated by survey year. The eligible sample can be identified by adding together the interviewed respondents and the respondents with a noninterview code in the original 'Reason for Noninterview' variables, those not marked 'Revised Deceased.'
Through the survey years there was concern that the number of respondents marked 'deceased' might be underreported and that some of the other 'Reason for Noninterview' categories might thus be overreported. In 2003, the Census Bureau, through the cooperation of the Social Security Administration, obtained SSA records for respondents who had shared their Social Security number with Census to verify whether respondents were living or deceased. As was previously suspected, a comparison of the SSA data with the survey data shows a substantially higher number of deceased respondents than was initially recorded. To correct for past survey discrepancies, a revised 'Reason for Noninterview--Revised/Deceased' variable using the SSA data was created for each survey year from 1970 on. These revised variables are R01338.20, R02053.30, R02883.30, R03084.30, R03295.30, R04565.30, R04912.30, R05284.30, R06664.40, R07215.40, R07833.40, R08878.40, R10093.40, R16014.20, R34985.20, R42671.20, R63203.30, and R76154.00. Researchers are urged to use these updated variables rather than the original 'Reason for Noninterview' variables.
Instructions to interviewers on how to code a respondent's reason for noninterview appear within the Interviewer's Reference Manuals (or Field Representative's Manuals). The set of noninterview coding categories present during the initial survey years has been supplemented over the years with additional reasons for noninterview, and the meanings of existing categories have been refined. Table 2.6.2 presents the raw coding categories present on the public data files and specifies the survey years during which each category was utilized.
| Conceptual Category | Raw Coding Category1 | Code & Survey Years | |
| CAN'T LOCATE | Unable to locate [contact] R - reason not specified | [1] | All (1967-2003) |
| [Unable to locate R] - mover - no good address | [4] | All | |
| INTERVIEW IMPOSSIBLE | [Unable to locate R] - mover - good address given but interview impossible to obtain (e.g., "moved to Germany" or "lives too far from PSU - distance too great")2 |
[2] | All |
| [Unable to locate R] - mover - good address given but unable to obtain interview after repeated attempts, etc. |
[3] | All | |
| [Unable to locate R] - nonmover - unable to obtain interview after repeated attempts, etc. |
[5] | All | |
| Temporarily absent | [6] | All | |
| Other | [11] | All | |
| REFUSAL | Refusal | [9] | All |
| Congressional refusal3 | [14] | 1984-2003 | |
| OUT OF SCOPE | In Armed Forces | [7] | All |
| Institutionalized | [8] | All4 | |
| Moved outside U.S. (other than Armed Forces) | [13] | 1979-2003 | |
| DECEASED | Deceased | [10] | All |
| DROPPED | Non-interview for two years, R dropped from sample | [12] | 1971-2003 |
| 1 Specific instructions to Census interviewers on use of these coding categories can be found in the cohort-specific Interviewer's Reference Manuals. |
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| 2 Beginning in the 1979 survey year, the separate "moved outside the U.S." coding category was added as a reason for noninterview and the "unable to locate" coding category no longer included those respondents who had moved outside the United States. |
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| 3 Congressional refusal refers to a congressional representative requesting a respondent not be contacted again for the NLS after a respondent has completed one or more survey rounds. |
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| 4 In 2003, interviewers sought out respondents in retirement communities, assisted living situations, and nursing homes. | |||
User Notes: Researchers can use the 'Reason for Noninterview' variables to identify respondents who were dropped from the eligible sample. Respondents with a code of 12 were dropped due to missing two consecutive interviews for reasons other than death or refusal. It is more difficult to determine which respondents were dropped because they refused an interview in 1981 or earlier, because they are assigned the same code as respondents refusing an interview in later years. To identify these respondents, researchers must examine the 'Reason for Noninterview' variables and assume that a respondent was dropped if she has a code of 9 for every survey since she first refused, if that first refusal was in 1981 or earlier. Respondents who have consistently refused in later surveys, but who did not refuse an interview before 1982, remain in the eligible sample. Note that, because respondents are asked to report activities since the date of the last interview, most information from missed interviews was retrieved if the respondent was subsequently interviewed. |
The reason for noninterview coding categories depicted in Tables 2.6.3 and 2.6.4 below were constructed from the raw coding categories as shown in Table 2.6.2. For example, the conceptual category "can't locate" is the sum of codes "1" and "4." Tables 2.6.3 and 2.6.4 depict the number of respondents not interviewed by survey year, reason, and race.
| Survey Year | Total Interviewed |
Total Not Interviewed |
Reason for Noninterview | |||||
| Can't Locate | Interview Impossible |
Refusal | Out of Scope1 | Deceased | Dropped2 | |||
| 1968 | 4910 | 173 | 49 | 25 | 76 | 1 | 22 | -- |
| 1969 | 4712 | 371 | 50 | 69 | 210 | 7 | 35 | -- |
| 1971 | 4575 | 508 | 56 | 65 | 294 | 6 | 58 | 29 |
| 1972 | 4471 | 612 | 39 | 49 | 390 | 2 | 71 | 61 |
| 1974 | 4322 | 761 | 41 | 31 | 481 | 5 | 100 | 103 |
| 1976 | 4172 | 911 | 34 | 40 | 581 | 7 | 131 | 118 |
| 1977 | 3964 | 1119 | 22 | 49 | 762 | 6 | 141 | 139 |
| 1979 | 3812 | 1271 | 21 | 27 | 866 | 11 | 183 | 163 |
| 1981 | 3677 | 1406 | 18 | 17 | 953 | 9 | 232 | 177 |
| 1982 | 3542 | 1541 | 14 | 26 | 1048 | 8 | 261 | 184 |
| 1984 | 3422 | 1661 | 30 | 25 | 1092 | 13 | 317 | 184 |
| 1986 | 3335 | 1748 | 37 | 35 | 1093 | 10 | 395 | 178 |
| 1987 | 3241 | 1842 | 30 | 45 | 1153 | 14 | 422 | 178 |
| 1989 | 3094 | 1989 | 29 | 49 | 1211 | 21 | 504 | 175 |
| 1992 | 2953 | 2130 | 60 | 18 | 1206 | 24 | 652 | 170 |
| 1995 | 2711 | 2372 | 68 | 89 | 1208 | 33 | 811 | 163 |
| 1997 | 2608 | 2475 | 94 | 49 | 1148 | 38 | 986 | 160 |
| 1999 | 2467 | 2616 | 78 | 67 | 1135 | 48 | 1131 | 157 |
| 2001 | 2318 | 2765 | 61 | 85 | 1078 | 55 | 1334 | 152 |
| 2003 | 2237 | 2846 | 36 | 47 | 1066 | 65 | 1485 | 147 |
| Note: This table is based on R00856.00, R00884.00, R01338.20, R02053.30, R02883.30, R03084.30, R03295.30, R04565.30, R04912.30, R05284.30, R06664.40, R07215.40, R07833.40, R08878.40, R10093.40, R16014.20, R34985.20, R42671.20, R63203.30, and R76154.00 |
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| 1 Beginning with the 1979 survey, "moved outside the U.S." became a separate out-of-scope coding category. Respondents who could not be interviewed during the 1968-77 surveys because their residence-either within or outside of the U.S.-was too far away were coded within the "interview impossible" category. Out-of-scope counts for pre-1979 survey years thus may be understated. |
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| 2 Respondents who had been noninterviews for two consecutive survey years due to reasons other than refusal or death were eliminated from the eligible sample beginning with the 1971 interview. After the 1982 interview, no additional respondents were dropped based on this rule. The number of respondents in this category has decreased steadily after 1982 due to the death rate of the respondents. |
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| Survey Year | Total Interviewed | Total Not Interviewed | Reason for Noninterview | |||||||||||||||
| Can't Locate | Interview Impossible | Refusal | Out of Scope1 | Deceased | Dropped2 | |||||||||||||
| Non-black | Black | Non-black | Black | Non-black | Black | Non-black | Black | Non-black | Black | Non-black | Black | Non-black | Black | Non-black | Black | |||
| 1968 | 3576 | 1334 | 117 | 56 | 26 | 23 | 16 | 9 | 60 | 16 | 1 | 0 | 14 | 8 | -- | -- | ||
| 1969 | 3418 | 1294 | 275 | 96 | 31 | 19 | 48 | 21 | 171 | 39 | 3 | 4 | 22 | 13 | -- | -- | ||
| 1971 | 3330 | 1245 | 363 | 145 | 29 | 27 | 52 | 13 | 229 | 65 | 1 | 5 | 32 | 26 | 20 | 9 | ||
| 1972 | 3264 | 1207 | 429 | 183 | 20 | 19 | 36 | 13 | 298 | 92 | 0 | 2 | 36 | 35 | 39 | 22 | ||
| 1974 | 3157 | 1165 | 536 | 225 | 19 | 22 | 24 | 7 | 370 | 111 | 3 | 2 | 55 | 45 | 65 | 38 | ||
| 1976 | 3049 | 1123 | 644 | 267 | 18 | 16 | 30 | 10 | 443 | 138 | 3 | 4 | 75 | 56 | 75 | 43 | ||
| 1977 | 2892 | 1072 | 801 | 318 | 12 | 10 | 36 | 13 | 582 | 180 | 3 | 3 | 81 | 60 | 87 | 52 | ||
| 1979 | 2781 | 1031 | 912 | 359 | 13 | 8 | 14 | 13 | 661 | 205 | 10 | 1 | 106 | 77 | 108 | 55 | ||
| 1981 | 2685 | 992 | 1008 | 398 | 9 | 9 | 13 | 4 | 731 | 222 | 6 | 3 | 134 | 98 | 115 | 62 | ||
| 1982 | 2583 | 959 | 1110 | 431 | 10 | 4 | 16 | 10 | 806 | 242 | 5 | 3 | 152 | 109 | 121 | 63 | ||
| 1984 | 2510 | 912 | 1183 | 478 | 15 | 15 | 16 | 9 | 838 | 254 | 11 | 2 | 182 | 135 | 121 | 63 | ||
| 1986 | 2453 | 882 | 1240 | 508 | 18 | 19 | 22 | 13 | 844 | 249 | 7 | 3 | 232 | 163 | 117 | 61 | ||
| 1987 | 2383 | 858 | 1310 | 532 | 18 | 12 | 34 | 11 | 884 | 269 | 10 | 4 | 247 | 175 | 117 | 61 | ||
| 1989 | 2277 | 817 | 1416 | 573 | 15 | 14 | 29 | 20 | 938 | 273 | 13 | 8 | 306 | 198 | 115 | 60 | ||
| 1992 | 2170 | 783 | 1523 | 607 | 36 | 24 | 13 | 5 | 953 | 253 | 15 | 9 | 394 | 258 | 112 | 58 | ||
| 1995 | 2012 | 699 | 1681 | 691 | 35 | 33 | 65 | 24 | 961 | 247 | 15 | 18 | 498 | 313 | 107 | 56 | ||
| 1997 | 1939 | 669 | 1754 | 721 | 67 | 27 | 35 | 14 | 921 | 227 | 22 | 16 | 604 | 382 | 105 | 55 | ||
| 1999 | 1848 | 619 | 1845 | 771 | 53 | 25 | 55 | 12 | 901 | 234 | 30 | 18 | 703 | 428 | 103 | 54 | ||
| 2001 | 1749 | 569 | 1944 | 821 | 43 | 18 | 66 | 19 | 859 | 219 | 35 | 20 | 843 | 491 | 98 | 54 | ||
| 2003 | 1693 | 544 | 2000 | 846 | 23 | 13 | 34 | 13 | 852 | 214 | 46 | 19 | 950 | 535 | 95 | 52 | ||
| Note: This table is based on R00023.00 (race), R00856.00, R00884.00, R01338.20, R02053.30, R02883.30, R03084.30, R03295.30, R04565.30, R04912.30, R05284.30, R06664.40, R07215.40, R07833.40, R08878.40, R10093.40, R16014.20, R34985.20, R42671.20, R63203.30, and R76154.00 | ||||||||||||||||||
| 1 Beginning with the 1979 survey, "moved outside the U.S." became a separate out-of-scope coding category. Respondents who could not be interviewed during the 1968-77 surveys because their residence--either within or outside of the U.S.--was too far away were coded within the "interview impossible" category. Out-of-scope counts for pre-1979 survey years thus may be understated. | ||||||||||||||||||
| 2 Respondents who had been noninterviews for two consecutive survey years due to reasons other than refusal or death were eliminated from the eligible sample beginning with the 1971 interview. After the 1982 interview, no additional respondents were dropped based on this rule. The number of respondents in this category has decreased steadily after 1982 due to the death rate of the respondents. | ||||||||||||||||||