Building on his clinical background in nursing and midwifery, Declan has developed a unique blend of experience in clinical trials, trials methodology, and evidence synthesis. This mix of clinical knowledge and trials expertise offers valuable insights across various clinical domains.

Declan has published over 260 papers (h-index 47 Scopus, April 2023), including more than 30 Cochrane systematic reviews, showcasing his skill in evidence synthesis. He has led a range of clinical trials with participant numbers from 100 to over 3,000 and is an active member of numerous national and international Trial Steering Committees and Data Monitoring Boards.