Here's the abstract:
This study examined the controversial practice of grade retention and children’s academic and behavioral adjustment using data from the Quebec Longitudinal Study of Kindergarten Children. We employed an autoregressive modeling technique to detect the impact of being held back during primary school on subsequent academic performance and behavioral development until age 12 years. The results indicate both a short- and long-term negative influence on academic performance for boys and girls. Children’s anxious, inattentive, and disruptive behaviors persisted and, in some cases, worsened after grade retention. These prospective associations were long lasting and more pronounced when grade retention occurred early in primary school. Boys were more vulnerable to the negative influence of grade retention on academic performance and classroom disruptiveness. Disruptive behavior in girls was comparatively less associated with long-term consequences than boys. Nevertheless, girls experienced both short and long-term academic performance problems in the aftermath of grade retention. Children’s prosocial behavior appeared unaffected by grade retention. These results are independent of what would have been expected by the natural course of academic and behavioral development.
So, if your hoping that this will make a kid better-behaved. Think again. According to this study, it actually makes the behavior worse. To me this is unsurprising. You take a kid out of a class with his age-peers, and put him or her into a class with kids a year younger. When you're talking about a 6-year old, or a 7-year old, that means being in a class with kids 17% and 14% younger, respectively. As any parent knows, there is a massive difference between a 6 year old and a 5 year old. The older kid plays differently, has a different vocabulary, is able to express themselves in far more complex ways. In short, a kid who is retained at an early age is stuck in a classroom with no true peer to play with or talk to.
This part cuts to the chase:
Positive effects of grade retention, if detected, are limited (Gottfredson et al., 1994) and tend to diminish over time (…). Two excellent examples make this point. First, Mantzicopoulosand Morrison (1992) observed an academic advantage for retained children during their 2nd year in kindergarten compared to their matched promoted peers. However, this advantage quickly faded by Grade 1, with retainees continuing to perform below the norm for their school district. Other studies have found similar effects (…). Second, Alexander, Entwisle, and Dauber (1994), monitored the school progress of 800 Baltimore children from first grade through middle school. More than 40% were held back during the study, with some twice. In some cases, the effects were positive. However, more profound examination of their data reveals less than positive outcomes. The largest group of retained children was one of first graders (n = 104). For these, the effects were quite discouraging. They did worse after retention than they did prior to retention. With retained second and third graders (…), the authors examined whether retention would curb academic free fall. Although these children benefited during the repeated year, they resumed their rank in percentile (in relation to their new same-grade peers) to where they were when they first started the repeated grade. Hence, it appears that grade retention is less than even a qualified success.
This is from the "Discussion", or conclusions of the article:
Grade retention negatively affected children's developmental outcomes regardless of the characteristics that they brought to their situation and the developmental trajectory predicted by such characteristics. These consequences were dramatic and often long lasting. In some cases, these varied according to sex. In others, grade retention affected children across the board.
....For both boys and girls, we found a sustained negative impact of grade retention on anxiety and inattentiveness. This impact was strongest for children who were retained in early primary school. The anxiety and inattentiveness problems were not only long lasting but became amplified over time. By the end of primary school, children who had been held back early on were worse off than those who had most recently been retained.
It is interesting to note that grade retention did not have an immediate effect on anxiety, but as children progressed in age and grade anxiety in those who were retained became significantly and increasingly problematic. Perhaps as children became older they became more conscious and identified by their peers as having been retained. Should this be case, such increases in academic status awareness could have induced evaluation anxiety, feelings of peer ridicule, and other social fit problems. For example, when it comes to choosing play partners, younger classmates show a tendency to choose nonretained classmates (i.e., their same-age peers) over retained classmates.
So, retention causes increased anxiety and isolation, without any academic benefit. Why are schools still insisting on this again?
Here's the final sentence:
Whether the practice continues because of inadequate alternatives or a commitment to school retention lore (...), this prospective study suggests that we should not underestimate the potential harm done by not using other means to intervene with academic failure.