Skip to main content

Table 1 The proportion of girls having had and not having had their first period, distributed by grade

From: Explaining differential item functioning focusing on the crucial role of external information – an example from the measurement of adolescent mental health

  Grade 5 Grade 7 Grade 9
n = 3174 n = 2929 n = 3168
Girls period 10.9% 70.7% 97.6%
Girls no period 89.1% 29.3% 2.4%