Initially trained as a psychologist in Aberdeen and Birmingham, David Hay moved to Australia in 1972. He worked at the La Trobe University in Melbourne until 1996 when he moved to Western Australia and Curtin University (link opens in new window).
David began the La Trobe Twin Study in 1976, covering all facets of the children's behavioral development at home and at school, with particular emphases on how twins may differ from singleborn children and on long-term predictors of behavioral problems. The study followed the development of over 2000 children (twins, their siblings and cousins - at that time there were too few triplets and higher multiples to be part of the study). One particular interest was speech and reading, leading to the analysis of multiple birth data from the 1975 National Survey of Literacy and Numeracy.
In the late 1980's he ran a study, "Having twins - how does the family cope?" This study followed expectant parents of twins from diagnosis until the children were six months old in order to clarify parents' main concerns and resource requirements.
David's systematic study of the needs of multiples in school, began in 1985 with a survey of 85% of all primary school teachers in South Australia. This was followed in 1986/87 with a nationwide survey of twins in primary school. In all some 800 parents and 1230 teachers (as many of the multiples were separated) took part in the study providing a uniquely comprehensive picture of twins in Australian schools. The survey was followed up by workshops in each state to address both local and general issues and a booklet "Twins in School" widely used in Australia, the UK and other countries.
Since 1991, he and his Sydney colleague, Assoc Prof. Florence Levy, have run the Australian ADHD Project (ATAP) which now involves some 27,000 family members. Results of their genetic studies can be found in their text "Attention, Genes and ADHD" published in 2001 by Bruner Routledge.
In Western Australia he and colleagues from the Institute of Child Health Research have developed the WA Twin Child Health Study (WATCH) which uses the unique record linkage in that state to identify all multiples and what has happened to them in terms of death, disability and progress.
Along with colleagues from Brisbane and London, he is currently working on a study of the adjustment of twins from preschool to school and whether the experience of being a twin helps or hinders their progress.
He has been National Patron of the Australian Multiple Birth Association (AMBA) for over 20 years and previously was a Vice-Chair of the International Society for Twin Studies (ISTS).