RESUMEN
Growing Up in Ireland (GUI) is the national longitudinal study of children and young people in the Republic of Ireland and has followed two cohorts for over ten years to date: Cohort '98 who were recruited into the study at age nine years and Cohort '08, recruited at age nine months. The study aims to describe the lives of Irish children and young people in terms of their development, with a view to positively affecting policies and services available for them. Traditionally, data collection involved in-home visits from an interviewer who conducted face-to-face interviews, recorded physical measurements of study participants and administered cognitive assessments. However, with the onset of the COVID-19 pandemic and the associated restrictions, significant adaptations were required to these methods to ensure data collection for the pilot and main fieldwork for Cohort '08 at age 13 could continue to the expected timeline. Face-to-face interviews with participants were replaced with telephone and web-based modes, interviewer training was conducted online, online resources were made available for interviewers and participants and COVID-19 related items were added to questionnaires. In addition to the scheduled data collection, a special COVID-19 survey was also conducted on both GUI cohorts in December 2020 to explore the impact of the pandemic on participants' lives. This paper outlines the adaptations made to traditional data collection methods in GUI, highlighting the challenges that were met, but also the benefits of some changes that may be worth incorporating into future waves of GUI.