Difference-in-difference analysis: The EU integration’s effect on quality of life through selected economic security indicators from 2005–2022

<p align="justify">Quality of life indicators are significant tools to evaluate the individual’s well-being. In this sense, economic security measurement is a part of well-being. In achieving a greater level of well-being, countries can get many benefits by joining economic integrations. However, these benefits may not only sometimes be as great as thought. We investigate the changes in (in)security measurements for the new members with the difference-in-difference method. This method is beneficial for analyzing the effects before and after treatment, policy, and implications for different units. Our study aims to detect if there are significant changes or improvements in the security levels of new members of the European Union from 2005 to 2022. The findings figure out that the level of <em>arrears</em> was essentially reduced for most members. Still, the integration has no visible impact on <em>purchasing power parity</em> for the period. These are critical findings showing a trend not sourced from integration and, at the same time, the inefficiency of policy and implementation of the EU.</p>