Internalizing problems were measured by the Internalizing subscale of the Achenbach scales with the same raters and scales as were used for externalizing problems, and were POM-rescaled. Cronbach’s alpha ranged from .81 to .90 for mothers, .82 to .84 for fathers, .85 to .91 for the teachers, .88 to .91 for self-reports on the YSR, and .89 to .92 for self-reports on the YASR, depending on the year, and was .89 for peers on the YASR. Correlations within year across raters ranged from .06 to .51 (p = .144 to < .001), depending on the year. Correlations within rater across years ranged from .34 to .79 for mothers, .29 to .63 for teachers, .58 to .79 for fathers, and .28 to .81 for self-reports (p < .001), depending on the year. Internalizing problems were averaged within developmental time frames (as listed in Table 1).
