If a child is failing, an extra year of instruction should result in mastery. It follows that once these students begin to achieve, their self-esteem will be enhanced. Of course teachers will be happy. They'll have homogenous classrooms making it easier for them to teach. Social promotion of students who are failing results in students with poor academic skills.
Retention seems like the correct answer, yet research indicates otherwise.
A meta-analysis is a statistical technique that can integrate the results of several studies to examine the effects of a variable such as retention. Results of this study found a significant grand mean effect size of -.37. In other words the retained students scored .37 standard deviations lower on the various outcome measures of the 44 studies. More specifically, results indicated significant differences between retained and promoted students on academic achievement, personal adjustment, self-concept, and attitude toward school. Promoted students had more preferred outcomes on all of these measures.