Assessment, Ahead of Print.
Several measures of adolescent optimism exist. However, none of these measures have been developed in the African setting, and only a few of the available measures have been validated for use in this setting. We aimed to develop and validate a culturally appropriate measure for this context. We employed an exploratory sequential mixed methods design using a five-step approach to tool development, comprising literature reviews, construct clarification, item development, piloting, and scale evaluation. We constructed a six-item scale, the Mabrouk’s Measure of Adolescent Optimism (MMAO). In a sample of 1616 adolescents from Kenya, the MMAO demonstrated adequate internal consistency (both Cronbach’s alpha and McDonald’s Omega > 0.80) and test–retest reliability (ICC = 0.46). Factor analysis supported a unidimensional scale with adequate criterion and divergent validity as well as measurement invariance across sex, age (younger vs. older adolescents), residence (rural vs. urban), schooling status (in-school vs. out-of-school adolescents), and language of administration (Swahili vs. English). We report on the development and validation of a new scale of adolescent optimism that can be used to assess optimism among adolescents in Kenya and similar contexts. Preliminary evidence shows support for this new measure’s reliability and validity, although additional tests are needed.