One of the most frequent question that is posed to me when I present my research on juku is: does supplementary education work? My two answers are: we don’t know, and it doesn’t matter for educational policy.
No Evidence of Efficacy of Supplementary Education
As to the first answer, we simply do not know whether various forms of supplementary education have any impact at all. There has been no careful and sustained research on this question that employs a credible scheme at controlling selection effects and we thus literally do not have an empirical clue.
Supplementary education advocates, especially if they are of the mind-set that the market and the introduction of market mechanisms “fix everything”, will respond that for-profit, fee-based supplementary education would not exist/continue to operate if it didn’t work.
That is not true, of course, and we might simply point to the large number of herbal and pharmaceutical remedies that lead a happy and profitable existence in the market place without any credible hints at their efficacy.
Just like health remedies, measurements of supplementary education generally only come after the fact. In the case of accelerated instruction, supplementary education is only tested at its very end point, often the sitting of a standardized examination. At that point in time, however, it is impossible to consider not having participated in supplementary education.
All the same arguments apply for specific tools, teaching aids, and pedagogies. While many of these are intuitively plausible (e.g., yes, I suspect that an engaged student learns more and faster, and retains more of the learned knowledge/skills), there is very limited research that employs control groups or proxies thereof in formal education research either.
Beyond the ethical questions of interventions in children’s education based on a randomized trial, the greatest hurdle would be that we consider so many different factors important in shaping education outcomes, that we would need very large samples that would be subject to very specific and well-defined supplementary education interventions to establish the beginning of a causal relationship.
Whether or Not Supplementary Education ‘Works’, Policy-Makers Should Take it Into Account
But whether or not supplementary education “works”, the fact of its global growth is based on a wide-spread belief in its efficacy. Japanese parents do not seem to go through much trouble in informing themselves about a particular juku beyond word-of-mouth and trial lessons, as far as I can tell from my interviews with juku operators. Word-of-mouth and trial lessons obviously only provide an indication of efficacy, but no real measure thereof. Nevertheless, parents and their children are clearly willing to take a leap of faith and believe that these kinds of tutoring “work”, or more plausible, they are simply too insecure and nervous to question the perceived efficacy when they see all their neighbours believe in efficacy claims and do not want little Takeshi or Yumiko to fall behind.
The large-scale participation of students in supplementary education clearly has an impact on the education system. Whether this impact is primarily in skewing access to education, a distortion in classroom dynamics, or an introduction of quasi-streaming, the impact is very real in many countries that have entered into an era of hypereducation. For policy-makers who are concerned about the impact that supplementary education is having (and concern can obviously range from outrage to encouragement) the fact that supplementary education may or may not “work” is therefore irrelevant.