Dr. Hal Willaby is a Research Fellow in the School of Public Health at the University of Sydney and at the National Centre for Immunisation Research and Surveillance (NCIRS). His PhD investigated the cognitive psychology of decision-making involving risk. He examined the relationship between non-rational beliefs and decisions involving risky choices, and used a PLS structural modeling approach to empirically validate a measure and test a novel theory. Throughout his PhD, Hal combined his understanding of cognitive psychology and the lab-based findings from his PhD to educate healthcare providers on risk perception and its relationship with compliance and concordance in patients with chronic disease. This work is continued at NCIRS, where he investigates psychosocial factors related to vaccine uptake. In particular, Hal is interested in determining the belief and attitude structures associated with risk perceptions of vaccine-hesitant parents, and validating a measure of those structures that can be used to inform targeted interventions. Hal is also contributing to the development and trial of the Vaccine Communication Framework – a motivational-interviewing resource for primary healthcare providers to address the concerns of vaccine-hesitant and vaccine-refusing parents.