I find the abstract fascinating. If I understand correctly, gifted identification... the gifted label... while not raising standardized test scores of a studied student population, appeared to have a positive impact on strengthening the students' non-cognitive skills such as motivation and self-discipline.
This makes me curious about the content and modus operandi of the gifted program and/or services these students were exposed to. Motivation, self-discipline, and other life skills such as resilience and persistence are indeed valuable traits to develop.
Thank you, Bostonian, for finding and posting this working paper, which definitely deserves some thought among the gifted community.