Dublin Anti-Bullying Self-Efficacy Scales aim to measure the effectiveness of
school anti-bullying programs in promoting five steps that victims and
bystanders take against online and offline bullying behaviors. These steps are
anti-bullying self-efficacy beliefs to recognize bullying behaviors, comprehend
emergency, take responsibility, know what to do, and intervene. However, when an
anti-bullying program is very effective for the majority of participants who
give high scores, a considerable number of participants who give low scores are
very likely to be detected as outliers. This raises two measurement issues.
First, high scores create highly negatively skewed data and lead to measuring a
unidimensional rather than multidimensional construct. This could be one reason
why recent research has been unclear about the extent to which the scales
measure a unidimensional, multidimensional, or bifactor construct. Second,
should outliers be removed or be considered as participants for whom the program
was ineffective? If the scales had measurement invariance across the group of
outliers and non-outliers or low and high self-efficacy, it could be concluded
that the anti-bullying program was ineffective for some participants. The
current research aims to address these issues by testing both measurement
invariance as well as unidimensional and bifactor models of anti-bullying
self-efficacy. Results of Pure Exploratory Bifactor (PEBI) Analyses and Item
Response Theory (IRT) with Two-Parameter-Logistic (2PL) Models of data from a
convenience sample of 14-year-old students in Ireland
(N= 1,222) indicated sufficient psychometric properties of
both unidimensional and multidimensional scales for victim offline, victim
online, bystander offline, and bystander online. Further research can use these
scales for measuring the bifactor model of anti-bullying self-efficacy as well
as the cut-off score for distinguishing between low and high anti-bullying
self-efficacy.