Data

This chapter gives detailed information about the data collection, the data set and the sample used for the analyses. The aim of this thesis is to show the impact of critical life events and the development of conjugal dynamics of couples living in Switzerland, hence a longitudinal data set is necessary. This study is based on the longitudinal data set “Social Stratification, Cohesion and Conflict in Contemporary Families”, a three-wave survey containing information about both partners of a couple. Many research projects analyse the internal dynamic and processes of conjugal life but often use data containing information given by only one partner of the couple.

Data sets consisting of information about both partners are still rare in sociology, especially in a longitudinal perspective (Huinink & Feldhaus, 2009). This shows already the advantage of the data set employed. It allows examining processes of couples, taking into account the perspective of both men and women over a time period of 13 years. The data set answers perfectly to the needs in order to answer the research questions as a result of several particularities:

• Information on both partners of the same couple are available at two points in time

• Information on different critical life events, which occurred between the observation period are available

• The data enables the measurement of conjugal interactions at two points in time, which is unique considering existing research literature

Data collection for the first wave of the study commenced in 1998 and was completed in 1999.

Using the Swiss directory, 5,652 possible participants have been detected randomly. They were contacted via mail in order to ask for their participation in the study. To be included in the sample, the contacted persons had to have been living together with their partner for at least one year and the partner had to accept to participate as well. Furthermore, the respondents had to be between 20 and 70 years old, heterosexual and resident in Switzerland (not necessarily with Swiss nationality), but able to speak one of the three official languages (German, French, Italian). 1,735 households accepted to participate, corresponding to a response rate of 31%.

20 Chapter 1 Data and Sample

Reasons for refusal were mainly the duration of the interview as well as the impression that the questions are too personal. The interviews were conducted using CATI (computer-assisted telephone interviews) and each partner has been interviewed separately from the other. The duration of each interview was about one hour. Most of the questions were answered by both partners, but some questions were asked by only one of them by random choice. The questionnaire was divided into several parts. It started with questions about the household compositions of the couple to obtain information about the presence, age and biological link of children, and also about the marital status of the couple. The next part covered the cohesion dimensions. Here, the focus was on questions about how partners are connected to each other and their social environment. The part termed regulation covered how partners organise their daily life together. Questions in this part asked about the participation in household tasks, about decision-making processes and also about how competencies and responsibilities are shared or regulated in the relationship. In the next part, respondents were asked to give information about critical situations in their relationship. First, there were questions about the occurrence of critical life events, such as accidents or illness, unemployment, financial problems or even the death of a child or spontaneous abortion. Furthermore, questions about conflictual situations have been asked as well as questions about problem-solving behaviour. The frequency as well as the severity of arguments and the process of conciliation are also included in this part. A short part asking about living conditions followed, preceding a larger part about the parent-child relationship. The part about the social networks of partners contained questions about the relationship with kinship as well as with friends. Those questions mainly covered the size of the different networks (kinship and friends) and the frequency of contacts with them. The evaluation of the relationship and the personal well-being as well as the attitudes towards norms and values followed in the next two sections of the questionnaire before the social participation was queried. The last part covered questions about the social-demographic factors of each respondent. At the end of the questionnaire, each respondent was asked whether he or she agreed to be re-contacted for the follow-up study, which was accepted by more than 90% of the men and women.

Finally, interviews with 1,534 couples were included in the sample of Wave 1. From the 1,735 households that accepted to participate, about 200 couples from the initial sample had to be eliminated because only one partner could have been interviewed up until the end of data collection, which meant that the interviews could not be used for the study, since the condition

1.1 Data 21

was that information of both partners had to be available. Almost half of the sample was living in the German-speaking part of Switzerland and one third in the French-speaking area; 20%

lived in the Italian-speaking part. Most of them were married (about 90%) and most relationships had existed already for ten years or more. About one third were childless, but approximately one third of the couples already had two children. More than 60% of the couples were living with children in the household (Kellerhals, Levy, Widmer, Ernst, & Hammer, 2000).

Table 1: Overview of the Sample in Wave 1

N %

The second wave of the study was conducted in 2004. The sample consisted only of women who had already participated in Wave 1. The concentration on women was made due to budget restrictions for this wave. This time, 70% of the women who took part in the first wave were available to be reinterviewed. Furthermore, the questionnaire was much shorter and focused mainly on the questions about conflicts and the evaluation of the relationship, as well as questions concerning the social network. Additionally, there was a question about the relationship status of the women. They were asked whether they are still in a relationship with the same partner as in the first wave. Around 7% of the 1,050 women participating in the second wave separated or divorced with their partner during the two observations.

22 Chapter 1 Data and Sample

The third wave was conducted in 2011 and our aim was to reinterview as many participants as possible who had already participated in the first wave. Therefore, all persons who agreed to be re-contacted in Wave 1 received a letter to inform them about the new wave and that they would be contacted within the subsequent weeks. Around 12% of the addresses were no longer valid, which can be explained due to the long time span between Wave 1 and Wave 3. Furthermore, there was a lack of young couples in the sample due to the time span between the two observations. In fact, there were no participants in the first wave who were less than 30 years of age. For this reason, a new cohort was added to the initial sample with couples where the woman was between 20 and 30 years old. With the help of the Federal Statistical Office of Switzerland (FSO), we received about 800 contact information of women aged 20 to 30 living with a male person in the household. The aim was to obtain information from ca. 200 young couples. The information received from the FSO did not necessarily contain the telephone numbers. Therefore, contact letters were sent to all listed persons to explain the aim of the study and to ask for participation. In addition, they were asked to give their telephone number if they wished to participate.

The conditions to be included in the final sample were different for the two sub-samples (participants of Wave 1 and new couples). Interviews with participants of the first wave were included even if only one partner agreed to participate. We did not want to drop them out, with the aim to retain them in the sample for further waves. Additionally, interviews of participants of Wave 1 have also been included even if they were no longer with the same partner, due to divorce or separation or even death of the partner. Hence, there are interviews in the sample with persons not living with a partner. They were asked to respond to a shorter version of the questionnaire. In case of separation or divorce, we tried to interview both ex-partners, and if any, the new partner as well. In contrast, for the new cohort the condition was that both partners answer the questionnaire.

A contact questionnaire with questions about the current relationship status and also about the number and presence of children was conducted prior to the main interview. In order to examine changes in the dynamic of conjugal life, the main questionnaire consisted of questions already asked in Wave 1 and also in Wave 2. The first and second part of the questionnaire contained questions about the cohesion and regulation dimensions. The questions were posed in the same way as in Wave 1. The third part contained questions about critical life events and conflictual situations in the relationship as well as about the evaluation of the relationship. The parent-child

1.1 Data 23

relationship followed in a short part before the section about social networks. The part about the evaluation of the personal well-being consisted on the one hand of questions already asked in Wave 1 but also contained a vulnerability scale, created by several researchers of LIVES¹. The so-called vulnerability scale is a tool to measure the vulnerability of individuals in certain life domains, such as work-related hassles, health-related problems or social isolation. The last section comprised questions about the social-demographic characteristics of the respondents.

Data collection took place between May 2011 and October 2011 using CATI.

The final data set includes 2,341 individuals; among these, there are 1,830 participants from the first wave, 486 participants from the new cohort and 25 new partners of participants in the first wave. Among the 1,830 participants in the first wave, there are interviews from both partners of 721 couples who are still living with the same partner as in 1998. There are an additional 169 individuals with the same partner as in 1998 in the sample, but only one of them participated in Wave 3. Among the respondents in Wave 1, 99 individuals who separated in between are included in the study. Only 25 interviews with the ex-partner and the new partners were possible to conduct. For the new cohort, only couples with answers of both partners are included in the sample. Consequently, 122 interviews had to be dropped from the sample, which leads to a final number of 182 couples in the new cohort. The response rate of the participants in the first wave is ca. 60%. More women (63%) than men (56%) of the first wave participated in Wave 3. Considering the whole sample of Wave 3 (participants of the first wave, new cohort and new partners), there are 48% men and 52% women. The median age for men is 54 and for women 51, hence the sample is older than the sample in Wave 1. The age group 31–40 years is heavily underrepresented. The composition of the sample regarding the language areas of Switzerland does not differ from the first wave (Veselá, Schicka, & Widmer, 2011). For the analyses, no weights were used. In the first wave, weights concerning the language areas were employed. However, we decided not to weight the data for the third wave. The decision was basically made due to the fact that we wanted to avoid weighting very small specific groups.

For example, in the third wave we have only a low proportion of men and women between 30 and 40 years. If we had weighted them, we would have risked overweighting their characteristics which are perhaps the characteristics of a very special group (for example, in 1 The Vulnerability Scale was mainly developped by researcher from the ip1 ("Vulnerability processes in adult life:

Cumulative disadvantages, critical events, and socio-psychosocial resources") of the NCCR LIVES leaded by Prof. Dario Spini.

24 Chapter 1 Data and Sample

terms of education or relationship quality). This could bias the results even more than working without weights.

Table 2: Overview of Participants in All Three Waves

Wave 1 Wave 2 Wave 3

1,535 couples 1,050 women 2,341 individuals

1,830 participants of Wave 1 182 couples of new cohort 721 couples with the same

Panel studies are always confronted with panel attrition, with a loss of participants over time.

Panel attrition has several reasons. The main reason is that over time people move away and they are no longer locatable. Furthermore, a loss of interest in the study can result in a loss of participants. In our study it is possible that panel attrition results from separation, which unfortunately cannot be tested here. However, we know that about 450 of the couples who participated in Wave 1 did not participate in Wave 3. We do not know the reasons for their non-participation. In any event, what we can test is whether those couples differ from those participating in Waves 1 and 3 regarding their socio-demographic characteristics and their relationship outcomes in Wave 1. If there are no significant differences between the two groups, it can be assumed that this sample is not biased by couples with positive relationship outcomes in Wave 1. Logistic regression models (Tables 3 and 4), with the non-participation as dependent variable, have been conducted in order to test the influence of relationship satisfaction, thoughts of separation and conflicts in Wave 1 on the non-participation of couples in Wave 3, as well as several socio-demographic characteristics. In this thesis, binary logistic regression analyses are employed several times. Regression analyses enable the researcher to detect the relationship between a dependent and one or several independent variables. The dependent variable must be dichotomised for binary logistic regressions (Hosmer & Lemeshow, 2000). Through the use of regression analyses, the probabilities of the dependent variables are estimated (Backhaus, Erichson, Plinke, & Weiber, 2011). The regression coefficient ß is estimated with the maximum likelihood function. The probability of the observed data as a function of the unknown