Group nouns can use either a single or plural form of the verb, but the choice should be consistent within each Cochrane review or document; for example, 'the government has ...' or 'the government have ...'.

In Cochrane reviews, ‘data' should always be treated as a plural noun, taking a plural verb (e.g. 'the data are ...', not 'the data is ...'). There is some debate about whether data can take the singular form of the verb when it is referring to a body of information rather than the actual numbers. In those cases, consider using a different word, such as ‘information’ or 'findings'.

'Errata', 'media', 'strata', and 'criteria' are plural nouns and take plural verbs.  The singular forms of these words are ‘erratum’, ‘medium’, ‘stratum’, and ‘criterion’, which take singular verbs.