Fair comparisons with few people or outcome events can be misleading.
With small samples and/or few outcome events, differences in outcome frequencies between the comparison groups may easily have occurred by chance and may mistakenly be attributed to differences between the interventions being compared.
However, this does not mean that all studies with small sample sizes should be rejected. Qualitative studies often have fewer participants as the aim is to describe certain behaviours in more depth. It is important that the methodology matches the aim of a study.
BEWARE of intervention comparisons with small samples and/or few outcome events. The results of such comparisons can be misleading (see also card on systematic reviews).
REMEMBER to check if the sample size is appropriate for the type of study that was carried out.