Final answer:
Research does not unequivocally support that adolescent employment has a negative impact on academic achievement; it could instead improve self-esteem, increase the risk of substance abuse, and enhance time management skills.
Step-by-step explanation:
The statement that is not supported by research with regard to adolescent employment is d) Negative impact on academic achievement. While it's true that excessive work hours can interfere with schooling, research does not unequivocally support the notion that adolescent employment has a negative impact on academic achievement. In some cases, students may develop better time management skills or a sense of responsibility that could positively affect their academic work. In contrast, a) Positive impact on self-esteem, b) Increased risk of substance abuse, and c) Improved time management skills are statements that have been supported by research to various extents. Specifically, having a job can boost adolescents' self-esteem and provide them with experience in managing their time effectively. However, there can also be an increased risk of substance abuse if the work environment exposes them to harmful behaviors or if they are using substances to cope with stress.