Observers and mothers rated infant behavior (n = 50) in the home on di
mensions of temperament once a week for 8 weeks. Although week-to-week
correlations were modest (intraclass correlations of .14-.36), aggreg
ates of the 8 observations had high reliability for both observers and
mothers. Mother reports were tied to our observation sessions by havi
ng mothers (a) rate their infants' behavior during the period when our
observations were made and (b) use a questionnaire that mirrored the
scoring system used for scoring the videotaped observation sessions. W
hen direct observations were compared with mother reports (on the aggr
egated weekly reports and on 4 widely used questionnaires), little evi
dence of mother-observer correspondence was found. The interpretation
of the large literature that has used maternal report is discussed, as
well as the importance of direct observation of infant behavior when
temperament is assessed.