Appendix 6: Event History Creation and Documentation

National Longitudinal Survey of Youth - 1997 Cohort

Appendix 6: Event History Creation and Documentation

Marital Status Event History Arrays

The NLSY97 marital and cohabitation arrays record changes in the respondent's marital status and cohabitation changes on a monthly basis. The marital/cohabitation history program converts dates reported in the marriage section (beginning and ending dates of cohabitations, marriages, separations, divorces, and widowhoods) to an actual month number, using January 1980 as month #1. Used jointly, these arrays allow the researcher to obtain a detailed history of the respondent's partners and changes in his/her marital and cohabitation status on a monthly basis. All marital/cohabitation arrays provide information beginning in the month that the respondent turned 14 (although respondents do not answer marriage and cohabitation questions until they reach age 16) and ending in the month that he or she was last interviewed. Additionally, the beginning dates of the youth's first marriage and first cohabitation and first divorce are provided in three variables: CVC_FIRST_MARRY_MONTH, CVC_FIRST_COHAB_MONTH, and CVC_FIRST_DIVORCE_MONTH. 

Three types of arrays record transitions between living without a partner of the opposite sex to cohabiting or to marriage.

1. MAR_STATUS
The main array presents the status (e.g., never married/not cohabiting, cohabiting, married, divorced) of a respondent during a particular month. Marital status takes precedence over cohabiting; for example, if a respondent is divorced and living with another partner, the status listed in this array will be 'divorced.' Respondents who are married but not living with their spouse are coded as married. If a respondent reports an annulment, the previously reported dates of marriage are maintained and the marital status code after the annulment is 'divorced.'

Missing and imputed values. Some respondents do not provide complete information about marriage and cohabitation dates.  In the creation of the event history arrays, these missing values are imputed so that an array can be constructed for each respondent.  Imputed values are as follows:

Type of Missing Data Imputed Value
Missing start date for marriage or cohabitation: both month and year missing Month and year are imputed to one month after the date of the respondent's last interview
Missing start date for marriage or cohabitation: year known, month missing January (of the known year) is assigned as the imputed start month of marriage/cohabitation
Missing start date for separation or divorce: both month and year missing Month and year are imputed to the month of the current interview
Missing start date for separation or divorce: year known, month missing December (of the known year) is assigned as the imputed date of separation/divorce
Missing end date for cohabitation: both month and year missing Month and year are imputed to one month before the month of the current interview
Missing end date for cohabitation: year known, month missing December (of the known year) is assigned as the imputed date of the end of cohabitation

2. MAR_COHABITATION
This second array details the partner that the respondent is living with in a particular month. For example, if the respondent is cohabiting, the variable for each month identifies whether the respondent lives with partner 1, partner 2, spouse 1, spouse 2, etc. Users should note that "1" and "2" in this case refer to the respondent's partners/spouses in chronological order. The numbers do not necessarily refer to the same person as the loop numbers in the spouse/partner questions asked directly of the respondent during the survey. Users can distinguish between partners and spouses because partner IDs begin with "1" (e.g., 101, 102) and spouse IDs begin with "2" (e.g., 201, 202). Using the partner ID, we also can count the total number of the cohabitation and total number of the marriage; for example, a code of 106 indicates the respondent has had a total of six partners from round one to current round. A code of 203 means the respondent has been married three times from round one till the current round.

Note that some respondents are married but are not living with their spouse. These respondents are coded as "married, spouse absent" in the created marital status variable (CV_MARSTAT), and in this array they will have a -4 (valid skip) rather than a partner ID. Additionally, a few respondents are married but cohabiting with someone other than their spouse.  These respondents are coded as "married, spouse absent" in the created marital status variable (CV_MARSTAT), and in this array they will have the ID of the partner they are cohabiting with (not the ID of the spouse).

3. MAR_PARTNER_LINK
The third array links the cohabiting partner or spouse to the partner order in the main survey questions. This array allows the researcher to identify characteristics of the respondent's partner and to link them with spells of marriage or cohabitation. For example, a researcher might look at the MAR_COHABITATION variable for the 9th month of 1998 and determine that a respondent was living with his second partner ever in that month because the variable's value is 102. The MAR_PARTNER_LINK variable provides a crosswalk between this value and the new partner ID variable on the partner roster (PARTNERS_ID ). The researcher can then examine the roster and survey variables for that partner to determine the person's characteristics, such as race, ethnicity, age, religion, and so on.

User Note

Researchers should be aware that the partner rosters were created for all rounds and released as part of the round 5 data set. Consequently, the partner link variable in the event history data (MAR_PARTNER_LINK) now uses those new IDs (PARTNERS_ID). This results in the ability to better link partners across rounds, so cohabitation (MAR_COHABITATION) and marital status arrays (MAR_STATUS) were updated for the round 5 event history release. These changes, combined with careful cleaning of the data, minimized the possibility that one spouse/partner is incorrectly recorded as a second spouse/partner due to the respondent reporting the same information in more than one interview. As a result, it is less likely that over counting of the total number of marriages and spells of cohabitation (MAR COHABITATION) will occur. The changes also reduced the number of dual partners reported (MAR_DUAL).

Other information
MAR_DUAL.
Rounds 1 and 2 contain a fourth monthly array. If there is an overlap of partners (e.g., partner 1 leaves at the beginning of the month and partner 2 moves in at the end of the month), this array records the presence of the new partner. The format of these variables is the same as the MAR_COHABITATION variables. Beginning in round 3, this array was changed to one single variable. Because this is a relatively rare event, there is only one variable per round that indicates whether there was any month with an overlap period between the current interview and the previous interview.

Denial of previous data. Occasionally, respondents report that the marital status information from a previous round is not true. As is the case with employment, the information in arrays based on that rounds' information is maintained, but the respondent is assigned a value in a flag variable (MAR_DENY) indicating later denial of the information. This flag variable has several different possible values, depending on the type of information denied. For example, assume a respondent reported cohabiting at the round 2 interview date but denied that the cohabitation had occurred in round 3. The status variables for each month from the beginning of the cohabitation to the round 2 interview date would continue to reflect the cohabitation, but the MAR_DENY variable would have a value of 3, indicating that the cohabitation was later denied. Starting from round 9, MAR_DENY is no longer available.