The word data is most often used as a singular collective mass noun in educated everyday usage.
[1][2] However, due to the history and etymology of the word, considerable controversy has existed on whether it should be considered a mass noun used with verbs conjugated in the singular, or should be treated as the plural of the now-rarely-used datum.
[20] The IEEE Computer Society allows usage of data as either a mass noun or plural based on author preference,[21] while IEEE in the editorial style manual indicates to always use the plural form.
[22] Some professional organizations and style guides[23] require that authors treat data as a plural noun.
For example, the Air Force Flight Test Center once stated that the word data is always plural, never singular.