Norell's research has encompassed a number of different areas, from the theoretical study of diversity through time, his doctoral dissertation on alligator phylogeny, and his postdoctoral work on evolutionary variations in maize.
at San Diego, Norell published papers on the efficacy of the fossil record in capturing phylogenetic history, and how missing data can influence the estimation of phylogeny.
Thus, guests begin their exploration with the simplest vertebrates, placoderms and bony fishes, and conclude their visit with advanced mammals, such as mammoths and artiodactyls.
Currently, Norell studies relationships of small carnivorous dinosaurs to modern birds and develops new ways of observing fossils through CT scans and imaging computers.
[5] Norell's theoretical work has a focus of data evaluation in large cladistic sets, as well as fossil pattern estimation through phylogeny, in order to see trends in diversity and extinction.