Table 1 Examples of classifying PRISMA items

Item common to all PRISMA extensions: ‘Describe the rationale for the review in the context of what is already known’

Item worded similarly, with important differences, across PRISMA extensions: PRISMA Harms recommends, ‘Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated’ [15]. PRISMA 2020 recommends, ‘Present the full search strategies for all databases, registers and websites, including any filters and limits used’ [21]

Item unique to a PRISMA extension: Only PRISMA NMA recommends, ‘Describe the statistical methods used to evaluate the agreement of direct and indirect evidence in the treatment network(s) studied’ [7]