Grade retention is a topic I have written about many times before. It can also lead to quite heated discussions in education. At the same time, the scientific consensus is fairly clear: it is generally not the best option. I know there are dissenting scientific voices, too. However, you still cannot avoid the question of whether this relatively costly intervention is always the best option. This is especially interesting because acceleration is something we do less often and frequently talk about much more negatively. Nevertheless, acceleration can actually have positive effects.
Why am I bringing this up today? A new study by Jiee Zhong of Miami University adds a striking possible extra dimension to the whole discussion. What does she find? Students who are retained at a young age may also earn less as young adults.
How did Zhong study this? In Texas, there was a policy for some time that required third-grade students to pass a standardized reading test to advance to the next grade. The children were given three attempts. The kids who still scored below a certain cutoff on the third attempt were, in principle, required to repeat the grade. Do note that there were exceptions.
And this approach created an interesting situation. Think of it, A student scoring, say, one point below the threshold will, on average, not be fundamentally different from a student scoring one point above it. At the same time, their chances of being retained will differ enormously. And indeed, scoring just below this threshold increased the probability of grade retention by 35.5 percentage points. This allows Zhong to compare students just above and just below the cutoff. Using a fuzzy regression discontinuity design, we can estimate the causal effect of grade retention.
Relevant to keep in the back of our mind is that the students on either side of the cutoff differed little in characteristics such as socioeconomic background, ethnicity, special education participation, English proficiency, or earlier mathematics achievement. There was only a small gender difference that was marginally statistically significant, with more boys just below the cutoff.
Now, how do we get from test results at around age nine to earnings many years later? Zhong can follow these particular students for years using administrative data. In the short term, grade retention seems to do what you might hope it would do. Reading performance initially improves, and so does mathematics performance. But, as we already know from other research, these benefits gradually disappear. A few years later, little of the original gain remains.
At the same time, other things happen too. Absenteeism increases among the students who were retained. In the first two years after a child had to redo a grade, this amounts to approximately 1.25 and 1.38 additional days absent per year, respectively. This is about 23 and 25 percent more than among students just above the cutoff. Zhong also finds more violent behaviour and juvenile crime among the retained students.
Grade retention in third grade also reduces the estimated probability of eventually obtaining a high school diploma by 9.1 percentage points. Among students just above the cutoff, 64.2 percent eventually obtained such a diploma.
When it comes to entering higher education, the picture becomes less clear. There are indications that retained students are somewhat more likely to attend a community college and somewhat less likely to attend a public university, but these differences are not statistically significant. The same is true for differences in eventually obtaining a college degree. So, little clear impact here. But Zhong can take things one step further.
Zhong was able to link the education records to earnings data from Texas. This allows her to see what happens when these young people enter the labour market. At age 26, students who were retained in third grade earn an estimated $3,477 less per year than comparable students who were promoted. Compared with the average earnings of students just above the cutoff, this amounts to roughly 19 percent lower earnings. If you average across ages 23 to 26, the estimated difference is $3,518 per year. This is about 21 percent.
A possible explanation, according to Zhong, may lie in processes I have already discussed earlier in this post. Processes that could negatively affect the likelihood of earning a diploma. This, in turn, can have repercussions for the kind of job you end up doing. Personally, I think this is quite plausible. But bear in mind, the study cannot establish this mechanism causally. The stronger causal argument concerns the effect of grade retention itself. It does not address the precise pathway through which the later earnings effect emerges.
I see another important caveat. We cannot use this study as evidence that grade retention is by definition harmful or that it will certainly reduce earnings later in life. You also cannot and should not conclude that every student who repeats a grade will later earn 19 percent less. The study examined students who were close to a very specific reading-performance cutoff in Texas.
The group Zhong studied also included a relatively large number of students from low-income families, Hispanic students, and students with limited English proficiency. Also, the rules on grade retention in Texas during this study were quite specific. Other education systems handle retention very differently. So the effects of grade retention could be very different in, say, England, Belgium, Australia, or any other education system.
What I think we can take from this study is that if you look only at test scores shortly after a student repeats a grade, you can’t tell whether grade retention was an effective intervention. Sometimes important negative side effects may emerge much later. Effects you would rather not have.