Her work has pioneered the use of isotope analysis in archaeology, specifically diet and climate in human and animal tissues.
She began to work with Robert Hedges at the Research Laboratory for Archaeology and the History of Art in Oxford initially during her undergraduate dissertation followed by a DPhil funded by SERC/NERC.
[1] O'Connell is a Fellow in Bioarchaeology and Director of Studies in Archaeology at Trinity Hall.
[4] She has supervised Phd students in isotopic archaeology, including Amy Prendergast, Suzanne Pilaar-Birch, and Emma Lightfoot.
[1] O'Connell has collaborated widely with archaeologists across time periods, including Roman Italy.