Until now, the conventional approach using two distinct groups, experimental and control, continues to dominate research, especially education research. Researchers, particularly those who are active in this domain, readily recognise this pattern when surveying literature. This article explores the use of the Solomon four-group design as a…

Pregnancy is a frequently applied exclusion criteria for many forms of research. Common justifications for this exclusion include the potential for teratogenicity, as well as the potential for physiologic changes in pregnancy to impact the research itself. The systematic exclusion of pregnant persons from clinical studies has created a significant…

Many interventions in education occur in settings where treatments are applied to groups. For example, a reading intervention may be implemented for all students in some schools and withheld from students in other schools. When such treatments are nonrandomly allocated, outcomes across the treated and control groups may differ due to the treatment…

The experiences and learning opportunities children are exposed to in pre-K give them a boost as they enter school. However, the positive effects of pre-K attendance on children's academic and cognitive skills become smaller and sometimes disappear by third grade due to non-attenders "catching-up" to their peers. To make pre-K programs…