The data collection, which started in 2018, was one of the first completed studies in a completely new research direction. To the best of our knowledge (based on the available publications), no similar data collection was done before our pilot research. We can only find 1-2 studies using this approach to date. Due to the innovative approach, there was no previous research experience for many questions, which required a very careful research design. Therefore, in the first half of the project, the research team carried out a project preparation, where we tested what data could be obtained using the data donation approach, what data could be requested, how to manage the technical implementation of the data collection and how to ensure maximum compliance with the various ethical and data protection rules. 

We commissioned a professional market research company to carry out the research. The sample size planned (and eventually implemented) was 150 people. A weak age quota was used in the study, with a minimum of 40 percent of the sample over 30 years. The sample is not a probability sample, so it does not represent Facebook users. Fieldwork was conducted between April and September 2019. Participants who agreed to take part in the study were sent a description of the project and received an invitation to the local office of the market research company. 
As well as sharing their Facebook details, participants were asked to complete an online questionnaire while in the office. The questionnaire covered various topics, including questions on politics, media use, self-presentation, mental health, leisure activities, and music preferences. The same identification code was used in the online questionnaire and when storing the Facebook data to link the two data sources. 
The complete processing of the data took almost two years due to the very complex data structure. With some restrictions, the final datasets were made available in the KDK research archive. The research is public at the following link: https://openarchive.tk.mta.hu/508/

The primary outcome of the research was the development and testing of a methodological framework for data donation. This will set the stage for further research of this kind. International conference presentations and publications have given the project significant visibility in the wider scientific community. National publications contribute to a deeper integration of Computational Social Science in the field. An important mission of our project is to ensure that the novel data generated are used as widely as possible. As part of this goal, we have dedicated several courses in the ELTE TÁTK training to research processing, both at BA and MA/MSC levels. In these courses, students were introduced to data collection, possible ways of data processing, and, in groups of 2-3 students, they also worked on a topic of their own. Several exciting analyses were produced based on the research, some available on the website. In addition to the courses, we have also made the anonymized data available to students for their thesis. By the end of the project, 3 MSc and one BA thesis were completed based on the data donation databases.

The project officially closed on 28 February 2022. However, the closure of the call does not mean the end of the data donation project. The principal investigator (Zoltán Kmetty) successfully applied for the ELKH Priority Research Grant, which awarded him 60 million HUF for a larger scale data donation project. The new project will collect data from a representative sample of 1000 people and target other platforms besides Facebook (Instagram, Google, Twitter). The latest research will be launched in December 2021 and will build on the results of the OTKA research presented here. This research is an essential cornerstone of our aim to make Budapest a cutting-edge digital data research center.