A considerable number of patients have to be recruited in a clinical trial
to obtain solid results. In pediatric studies, patient recruitment is frequ
ently problematic. In the simple common childhood illnesses, the number of
recruitable patients is certainly large, but they may be hard to reach, and
the imbalance between potential benefit and inconvenience of participation
may reduce motivation to enroll. In severe diseases, the balance may be ri
ght, but the available number of patients may be small. Good communication
with the child and family, as well as the motivation of colleagues to admit
, is another key element in success. Proper study design, including realist
ically identified sources of patients, reasonable inclusion, and exclusion
criteria, also are required.