To measure knowledge about breastfeeding, the
investigators used a 50-item Breastfeeding Comprehensive
Knowledge Survey (BCKS) instrument
developed by Harris and Miller (2005). Survey
items measure basic and advanced breastfeeding
knowledge and are presented in a multiple choice
format. Content validity was established based on
a review of literature and a consensus of 10 lactation
consultants and a physician renowned for breastfeeding
expertise. Although there are no prior
psychometrics for this tool, internal consistency reliability
for the BCKS in the current study was
supported with a Spearman-Brown coefficient of
.73 (Table 1). The Spearman-Brown coefficient is an
appropriate reliability test when all of the items are
dichotomous, that is, correct or incorrect (Garson,
2010b).