Below we will answer some questions that came up in connection with Cohort ‘18. If you have additional questions, feel free to contact us at the This email address is being protected from spambots. You need JavaScript enabled to view it. e-mail address.

The objective of the Cohort ‘18 study is to track the lives of children born in Hungary in one generation and their families from their gestational life to early childhood, examining how the children’s course of life is influenced by their family background, living conditions, physical and social environment, physical and psychological development, and health status.
The research is conducted by the Hungarian Demographic Research Institute, in cooperation with the network of health visitors and several external experts (see Staff and Advisory Bodies).
The word “cohort" refers to a group of people that experience some life event at the same time. Cohort ‘18 is a birth cohort study, since children to be born in the same time period, between April 1, 2018 and April 30, 2019, are included in the sample. The ‘18 number in the title of the research refers to the year in which the first, prenatal data collection takes place (but some babies included in the study will be born in 2019).
There have been studies similar to Cohort ‘18 conducted in several countries of the world (see Related research), but a so large-scale birth cohort study bringing together several disciplines has not yet been launched in Central-Eastern Europe. Therefore, this is the first opportunity in this region to learn about the development and growing up of children while considering several aspects. Cohort ‘18 stands out from among the international studies as well, because – thanks to the network of health visitors – we can get to know the expecting family even before the child is born.
The group of participants for the Cohort ‘18 study was defined by selecting health visitor districts with mathematical and statistical methods. In these districts, we invite all of the pregnant women to participate if their child is expected to be born between April 1, 2018 and April 30, 2019. In selecting the districts, our aim was to have pregnant women in the sample who represent all the pregnant women in the country on a small scale. In order to keep the group of participants diverse and get to know several kinds of opinion, it is crucial to have the pregnant women invited participate in the research. Children and their families involved in the research will represent all children born in the country during this time period.
Yes. The selected districts are the initial sample of the research, so in case you are ready to participate, and answer the prenatal questionnaire administered by your health visitor, then you and your child will remain participants of Cohort ‘18. It is important that you should let us know about your new address, enabling us to contact you later. You can read more about this possibility here.
During the research, the survey of the same families will take place through questionnaires administered at various times. There will be five interviews in the present phase of the research. The first two questionnaires will be administered by the health visitor during pregnancy and when the child is six months old. This will be followed by interviews when the child is eighteen months and three years old, conducted by professional interviewers of HDRI. In addition, we would like to conduct a shorter interview when the children enter an institution. Surveys consist of verbal interviews with the natural mother/stepmother/primary caretaker and her filling out the self-administered questionnaire. With the participants’ consent, we also include health and administrative data in the database. The research does not involve additional medical checkups, neither for the pregnant woman, nor for the child to be born.
Research financing is presently ensured until 2022, the time of the three-year interview. Of course, a birth cohort study is most beneficial on the long run if researchers can track the growing up of the child all the way into adulthood. We also plan to contact the children in the sample later on, less frequently, at the most important periods of their lives. We will inform the participants about the details as the research unfolds.
The advantage of studies such as Cohort ‘18 is that the life-course of children participating in the study can be tracked, revealing the real life stories of children and the cause and effect correlations playing a role in their development. If we ask different persons at different dates, we can only get a less accurate picture of their past from reminiscences, but if we contact the same people from time to time, then the course of life reveals itself in more detail. This enables us to examine from several viewpoints the things that assist and those that hinder the development of the child. Of course, the course of life is studied on aggregated data only, with reference to specific groups of children.
Cohort ‘18 is primarily a social science research, but it also includes other disciplines (psychology, economy, health) that are especially important in the development of children. Our basic objective is to get to know the family of the child to be born, so the first questionnaire also includes questions about the father and the siblings. In addition, we touch upon the household, its financial situation, and details on the mother’s health status, feelings, expectations and plans. Later on, we would like to get a view on the physical and cognitive development of the child, and on all the factors that may influence this, including the circumstances of the delivery, changes in the family, changing roles within the family, and the employment of mothers.
Although it is very important for us to see the development of the child from both the mother’s and the father’s perspective, it is not possible for us to interview both the mothers and the fathers in each data collection phase. We plan to contact the fathers when the child is eighteen months old, with a questionnaire especially designed for them, and ask the mothers about the fathers during the rest of the interviews.
We conduct the research in accordance with the law on data protection and statistics. In order to be able to handle your answers to the questionnaire and your data in the health care system, we ask you to sign an informed consent. By signing this consent, you confirm that you know about the course of research and agree to participate in it. You can read more about the consent and our data protection principles at the Data protection section.
The health visitor assigns a six-digit identifier to each fetus, which will stay with the child throughout the research. This identifier enables us to leave out personal data from the database used by the researchers and merge the various research databases (e.g. answers to the prenatal questionnaire and answers to the self-administered questionnaire) without personal data.
The essence of the research is that we can contact the same families and children from time to time. We need your address, phone, and other contact information only to enable the health visitor (and later the interviewer) to contact you or make an appointment with you in advance. We will store your address and contact information separate from your answers for the questionnaire, in a non-accessible database, and will use it exclusively for keeping in touch.
The personal data and the social security of the mother (which initially identifies the child to be born) and then the personal data of the child enables us to connect data from the health care, state public service and public administration system with the database. Through data connection, we can add crucially important data to the database, such as the circumstances of prenatal care and delivery, or admission to nursery/kindergarten/school. Data connection relieves the burden of the respondent, since we do not need to ask you for this data, we can simply ask them from the appropriate institutions through your personal data and insert them into the database with the help of help of identifiers used in the research. This database, accessible for the researchers, does not include the social security number or any data suitable for personal identification.
The research data, marked by the identifiers used in the research, goes into an aggregated database, which does not contain personal data. Their scientific analysis will take place at aggregated level, with statistical methods. We will store personal data (name, address, social security number) in a secured database, separate from the research data, and only authorized members of the research staff will be able to manage them, in accordance with data protection laws.
Children included in the sample are special, because it is through their lives that we learn about the circumstances of families with small children, and what growing up in Hungary is like. By answering the questionnaire, the parents contribute to several disciplines getting a clear picture on factors that advance the development of the child, and on how the disadvantages could be curtailed, and the progress supported. Families participating in the research will continue to receive information about the results of Cohort ‘18. In addition, we will seek to share information, news and recommendations with our respondents through our homepage and Facebook page that can help them in their daily lives and answer their questions about the development of young children.