In practice, the usage of the words data and datum in published scientific work seems to vary depending on how much of a grammarian an author's co-authors
or editors are. For papers I have written for conferences
and journals, my dissertation advisor (who was learning Latin) always demanded that I write "the
data show", as in "the image interpolation data show that Britney Spears has breast implants", rather than "the image interpolation data shows" the same thing. His rationale for this demand was based on
the idea that conference papers and journals were formally
published work that may be read by others years or decades
later. As such, he believed that correct grammar should be
used.