Amount of data (number of participants)	"Test for small‐study effects (large vs small studies)"	Action	Reason
≥ 1500 participants, many studies, events common	Small‐study effects absent	Do not downgrade	Large amount of data, no obvious size bias, randomness not at issue
≥ 1500 participants, many studies, events common	Small‐study effects present, or not possible to test	Downgrade once, emphasise sensitivity analysis result	Large amount of data, obvious size bias, randomness not at issue
400‐1499 participants, many studies, events common	Small‐study effects absent	Downgrade once, limited ability of sensitivity analysis to determine small‐study effects	Possible size bias and randomness effects may be present
400‐1499 participants, many studies, events common	Small‐study effects present, or not possible to test	Downgrade twice, emphasise sensitivity analysis result	Obvious size bias, and randomness effects may be present
≤ 400 participants, few studies, events common	Not possible to test for small‐study effects	Downgrade three times	Effects of random chance large, possibility of small size bias is high