With a Great Principal, Any Program Works. Right?

Whenever I speak about proven programs in education, someone always brings up what they consider a damning point. “Sure, there are programs proven to work. But it all comes down to the principal. A great principal can get any program to work. A weak principal can’t get any program to work. So if it’s all about the quality of principals, what do proven programs add?”

To counter this idea, consider Danica Patrick, one of the winningest NASCAR racecar drivers a few years ago. If you gave Danica and a less talented driver identical cars on an identical track, Danica was sure to win.blog_8-16_18_Danica_500x333But instead of the Formula 1 racecar she drove, what if you gave Danica a Ford Fiesta? Obviously, she wouldn’t have a chance. It takes a great car and a great driver to win NASCAR races.

Back to school principals, the same principle applies. Of course it is true that great principals get great results. But they get far better results if they are implementing effective programs.

In high-quality evaluations, you might have 50 schools assigned at random, either to use an experimental program or to a control group that continues doing what they’ve always done. There would usually be 25 of each in such a study. Because of random assignment, there are likely to be the same number of great principals, average principals, and less than average principals in each group. Differences in principal skills cannot be the reason for any differences in student outcomes, because of this distribution of great principals across experimental and control groups. All other factors, such as the initial achievement levels of schools, socioeconomic factors, and talents of teachers, are also balanced out by random assignment. They cannot cause one group (experimental) to do better than another (control), because they are essentially equal across the two sets of schools.

It can be true that when a developer or publisher shows off the extraordinary success of a school or two, the exceptional outcomes may be due to a combination of a great program and a great principal. Danica Patrick in a superior car would really dominate a less skilled driver in a less powerful car. The same is true of programs in schools. Great programs led by great principals (with great staffs) can produce extraordinary outcomes, probably beyond what the great principals could have done on their own.

If you doubt this, consider Danica Patrick in her Ford Fiesta!

Photo credits: Left: By Sarah Stierch [CC BY 4.0  (https://creativecommons.org/licenses/by/4.0)], from Wikimedia Commons; Right: By Morio [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], from Wikimedia Commons

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.


Elementary Lessons from Junior Village

When I was thirteen, I spent a summer as a volunteer at a giant orphanage in Washington, DC. Every child was African-American, and from an extremely disadvantaged background. Every one had surely experienced unspeakable trauma: death or desertion of parents, abuse, and neglect.

I was assigned to work with fourth and fifth grade boys. We played games, sang songs, did crafts, and generally had a good time. There was a kind volunteer coordinator who gave each of us volunteers a few materials and suggestions, but otherwise, as I recall, each one or two of us volunteers, age 13 to 16, was responsible for about 20 kids, all day.

I know this sounds like a recipe for chaos and disaster, but it was just the opposite. The kids were terrific, every one. They were so eager for attention that everywhere I went, I had three or four kids hanging on to me. But the kids were happy, engaged, loving, and active. I do not recall a single fight or discipline problem all summer. I think this summer experience had a big impact on my own choice of career.


There are two reasons I bring up Junior Village. First, it is to reinforce the experience that most elementary school teachers have, even in the most challenged and challenging schools. There are many problems in such schools, but the kids are great. Elementary-aged kids everywhere respond positively to just a little kindness and attention. I’ve visited hundreds of elementary schools over my career, and with few exceptions, these are happy and productive places with sweet and loving kids, no matter where they are.

Second, the observation that elementary-aged children are so wonderful should make it clear that this is the time to make certain that every one of them is successful in school. Middle and high school students are usually wonderful too, but if they are significantly behind in academics, many are likely to start a process that leads to disengagement, failure, acting out, and dropping out.

Evidence is mounting that it is possible to ensure that every child from any background, even the most disadvantaged, can be successful in elementary school (see www.evidenceforessa.org). Use of proven whole-school and whole-class approaches, followed up by one-to-small group and one-to-one tutoring for those who need them, can ensure success for nearly all students. A lot can be done in secondary school too, but building on a solid foundation from sixth grade forward is about a million times easier than trying to remediate serious problems (a privileged glimpse into the perfectly obvious).

Nationwide, we spend a lot more on secondary schools than on elementary schools. Yet investing in proven programs and practices in elementary school can ensure uniformly successful students leaving elementary school ready and eager to achieve success in secondary school.

I remember participating many years ago in a meeting of middle school principals in Philadelphia. The district was going to allocate some money for innovations. A district leader asked the principals if they would rather have the money themselves, or have it spent on improving outcomes in the elementary grades. Every one said, “Spend it early. Send us kids who can read.”

If you think it is not possible to ensure the success of virtually every child by the end of elementary school, I’d encourage you to look at all the effective whole-school, whole-class, one-to-small group, and one-to-one tutoring programs proven effective in the elementary grades. But in addition, go visit kids in any nearby elementary school, no matter how disadvantaged the kids are. Like my kids at Junior Village, they will revive your sense of what is possible. These kids need a fair shot at success, but they will repay it many times over.

Photo credit: By U.S. Fish and Wildlife Service Southeast Region [CC BY 2.0  (https://creativecommons.org/licenses/by/2.0) or Public domain], via Wikimedia Commons

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.

Preschool is Not Magic. Here’s What Is.

If there is one thing that everyone knows about policy-relevant research in education, it is this: Participation in high-quality preschool programs (at age 4) has substantial and lasting effects on students’ academic and life success, especially for students from disadvantaged homes. The main basis for this belief is the findings of the famous Perry Preschool program, which randomly assigned 128 disadvantaged youngsters in Ypsilanti, Michigan, to receive intensive preschool services or not to receive these services. The Perry Preschool study found positive effects at the end of preschool, and long-term positive impacts on outcomes such as high school graduation, dependence on welfare, arrest rates, and employment (Schweinhart, Barnes, & Weikart, 1993).


But prepare to be disappointed.

Recently, a new study has reported a very depressing set of outcomes. Lipsey, Farran, & Durkin (2018) published a large, randomized study evaluating Tennessee’s statewide preschool program. 2990 four year olds were randomly assigned to participate in preschool, or not. As in virtually all preschool studies, children who were randomly assigned to preschool scored much better than those who were assigned to the control group. But these results diminished in kindergarten, and by first grade, no positive effects could be detected. By third grade, the control group actually scored significantly higher than the former preschool students in math and science, and non-significantly higher in reading!

Jon Baron of the Laura and John Arnold Foundation wrote an insightful commentary on this study, noting that when such a large, well-done, long-term, randomized study is reported, we have to take the results seriously, even if they disagree with our most cherished beliefs. At the end of Baron’s brief summary was a commentary by Dale Farran and Mark Lipsey, two the study’s authors, telling the story of the hostile reception to their paper in the early childhood research community and the difficulties they had getting this exemplary experiment published.

Clearly, the Tennessee study was a major disappointment. How could preschool have no lasting effects for disadvantaged children?

Having participated in several research reviews on this topic (e.g., Chambers, Cheung, & Slavin, 2016), as well as some studies of my own, I have several observations to make.

Although this may have been the first large, randomized evaluation of a state-funded preschool program in the U.S., there have been many related studies that have had the same results. These include a large, randomized study of 5000 children assigned to Head Start or not (Puma et al., 2010), which also found positive outcomes at the end of the pre-K year, but only scattered lasting effects after pre-K. Very similar outcomes (positive pre-k outcomes with little or no lasting impact) have been found in a randomized evaluation of a national program called Sure Start in England (Melhuish, Belsky, & Leyland, 2010), and one in Australia (Claessens & Garrett, 2014).

Ironically, the Perry Preschool study itself failed to find lasting impacts, until students were in high school. That is, its outcomes were similar to those of the Tennessee, Head Start, Sure Start, and Australian studies, for the first 12 years of the study. So I suppose it is possible that someday, the participants in the Tennessee study will show a major benefit of having attended preschool. However, this seems highly doubtful.

It is important to note that some large studies of preschool attendance do find positive and lasting effects. However, these are invariably matched, non-experimental studies of children who happened to attend preschool, compared to others who did not. The problem with such studies is that it is essentially impossible to statistically control for all the factors that would lead parents to enroll their child in preschool, or not to do so. So lasting effects of preschool may just be lasting effects of having the good fortune to be born into the sort of family that would enroll its children in preschool.

What Should We Do if Preschool is Not Magic?

Let’s accept for the moment the hard (likely) reality that one year of preschool is not magic, and is unlikely to have lasting effects of the kind reported by the Perry Preschool study (and no other randomized studies.) Do we give up?

No.  I would argue that rather than considering preschool magic-or-nothing, we should think of it the same way we think about any other grade in school. That is, a successful school experience should not be one terrific year, but fourteen years (pre-k to 12) of great instruction using proven programs and practices.

First comes the preschool year itself, or the two year period including pre-k and kindergarten. There are many programs that have been shown in randomized studies to be successful over that time span, in comparison to control groups of children who are also in school (see Chambers, Cheung, & Slavin, 2016). Then comes reading instruction in grades K-1, where randomized studies have also validated many whole-class, small group, and one-to-one tutoring methods (Inns et al., 2018). And so on. There are programs proven to be effective in randomized experiments, at least for reading and math, for every grade level, pre-k to 12.

The time has long passed since all we had in our magic hat was preschool. We now have quite a lot. If we improve our schools one grade at a time and one subject at a time, we can see accumulating gains, ones that do not require waiting for miracles. And then we can work steadily toward improving what we can offer children every year, in every subject, in every type of school.

No one ever built a cathedral by waving a wand. Instead, magnificent cathedrals are built one stone at a time. In the same way, we can build a solid structure of learning using proven programs every year.


Baron, J. (2018). Large randomized controlled trial finds state pre-k program has adverse effects on academic achievement. Straight Talk on Evidence. Retrieved from http://www.straighttalkonevidence.org/2018/07/16/large-randomized-controlled-trial-finds-state-pre-k-program-has-adverse-effects-on-academic-achievement/

Chambers, B., Cheung, A., & Slavin, R. (2016). Literacy and language outcomes of balanced and developmental-constructivist approaches to early childhood education: A systematic review. Educational Research Review 18, 88-111.

Claessens, A., & Garrett, R. (2014). The role of early childhood settings for 4-5 year old children in early academic skills and later achievement in Australia. Early Childhood Research Quarterly, 29, (4), 550-561.

Inns, A., Lake, C., Pellegrini, M., & Slavin, R. (2018). Effective programs for struggling readers: A best-evidence synthesis. Paper presented at the annual meeting of the Society for Research on Educational Effectiveness, Washington, DC.

Lipsey, Farran, & Durkin (2018). Effects of the Tennessee Prekindergarten Program on children’s achievement and behavior through third grade. Early Childhood Research Quarterly. https://doi.org/10.1016/j.ecresq.2018.03.005

Melhuish, E., Belsky, J., & Leyland, R. (2010). The impact of Sure Start local programmes on five year olds and their families. London: Jessica Kingsley.

Puma, M., Bell, S., Cook, R., & Heid, C. (2010). Head Start impact study: Final report.  Washington, DC: U.S. Department of Health and Human Services.

Schweinhart, L. J., Barnes, H. V., & Weikart, D. P. (1993). Significant benefits: The High/Scope Perry Preschool study through age 27 (Monographs of the High/Scope Educational Research Foundation No. 10) Ypsilanti, MI: High/Scope Press.


This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.

What’s the Evidence that Evidence Works?

I recently gave a couple of speeches on evidence-based reform in education in Barcelona.  In preparing for them, one of the organizers asked me an interesting question: “What is your evidence that evidence works?”

At one level, this is a trivial question. If schools select proven programs and practices aligned with their needs and implement them with fidelity and intelligence, with levels of resources similar to those used in the original successful research, then of course they’ll work, right? And if a school district adopts proven programs, encourages and funds them, and monitors their implementation and outcomes, then of course the appropriate use of all these programs is sure to enhance achievement district-wide, right?

Although logic suggests that a policy of encouraging and funding proven programs is sure to increase achievement on a broad scale, I like to be held to a higher standard: Evidence. And, it so happens, I happen to have some evidence on this very topic. This evidence came from a large-scale evaluation of an ambitious, national effort to increase use of proven and promising schoolwide programs in elementary and middle schools, in a research center funded by the Institute for Education Sciences (IES) called the Center for Data-Driven Reform in Education, or CDDRE (see Slavin, Cheung, Holmes, Madden, & Chamberlain, 2013). The name of the program the experimental schools used was Raising the Bar.

How Raising the Bar Raised the Bar

The idea behind Raising the Bar was to help schools analyze their own needs and strengths, and then select whole-school reform models likely to help them meet their achievement goals. CDDRE consultants provided about 30 days of on-site professional development to each district over a 2-year period. The PD focused on review of data, effective use of benchmark assessments, school walk-throughs by district leaders to see the degree to which schools were already using the programs they claimed to be using, and then exposing district and school leaders to information and data on schoolwide programs available to them, from several providers. If districts selected a program to implement, their district and school received PD on ensuring effective implementation and principals and teachers received PD on the programs they chose.


Evaluating Raising the Bar

In the study of Raising the Bar we recruited a total of 397 elementary and 225 middle schools in 59 districts in 7 states (AL, AZ, IN, MS, OH, TN). All schools were Title I schools in rural and mid-sized urban districts. Overall, 30% of students were African-American, 20% were Hispanic, and 47% were White. Across three cohorts, starting in 2005, 2006, or 2007, schools were randomly assigned to either use Raising the Bar, or to continue with what they were doing. The study ended in 2009, so schools could have been in the Raising the Bar group for two, three, or four years.

Did We Raise the Bar?

State test scores were obtained from all schools and transformed to z-scores so they could be combined across states. The analyses focused on grades 5 and 8, as these were the only grades tested in some states at the time. Hierarchical linear modeling, with schools nested within districts, were used for analysis.

For reading in fifth grade, outcomes were very good. By Year 3, the effect sizes were significant, with significant individual-level effect sizes of +0.10 in Year 3 and +0.19 in Year 4. In middle school reading, effect sizes reached an effect size of +0.10 by Year 4.

Effects were also very good in fifth grade math, with significant effects of +0.10 in Year 3 and +0.13 in Year 4. Effect sizes in middle school math were also significant in Year 4 (ES=+0.12).

Note that these effects are for all schools, whether they adopted a program or not. Non-experimental analyses found that by Year 4, elementary schools that had chosen and implemented a reading program (33% of schools by Year 3, 42% by Year 4) scored better than matched controls in reading. Schools that chose any reading program usually chose our Success for All reading program, but some chose other models. Even in schools that did not adopt reading or math programs, scores were always higher, on average, (though not always significantly higher) than for schools that did not choose programs.

How Much Did We Raise the Bar?

The CDDRE project was exceptional because of its size and scope. The 622 schools, in 59 districts in 7 states, were collectively equivalent to a medium-sized state. So if anyone asks what evidence-based reform could do to help an entire state, this study provides one estimate. The student-level outcome in elementary reading, an effect size of +0.19, applied to NAEP scores, would be enough to move 43 states to the scores now only attained by the top 10. If applied successfully to schools serving mostly African American and Hispanic students or to students receiving free- or reduced-price lunches regardless of ethnicity, it would reduce the achievement gap between these and White or middle-class students by about 38%. All in four years, at very modest cost.

Actually, implementing something like Raising the Bar could be done much more easily and effectively today than it could in 2005-2009. First, there are a lot more proven programs to choose from than there were then. Second, the U.S. Congress, in the Every Student Succeeds Act (ESSA), now has definitions of strong, moderate, and promising levels of evidence, and restricts school improvement grants to schools that choose such programs. The reason only 42% of Raising the Bar schools selected a program is that they had to pay for it, and many could not afford to do so. Today, there are resources to help with this.

The evidence is both logical and clear: Evidence works.


Slavin, R. E., Cheung, A., Holmes, G., Madden, N. A., & Chamberlain, A. (2013). Effects of a data-driven district reform model on state assessment outcomes. American Educational Research Journal, 50 (2), 371-396.

Photo by Sebastian Mary/Gio JL [CC BY-SA 2.0  (https://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.

First There Must be Love. Then There Must be Technique.

I recently went to Barcelona. This was my third time in this wonderful city, and for the third time I visited La Sagrada Familia, Antoni Gaudi’s breathtaking church. It was begun in the 1880s, and Gaudi worked on it from the time he was 31 until he died in 1926 at 74. It is due to be completed in 2026.

Every time I go, La Sagrada Familia has grown even more astonishing. In the nave, massive columns branching into tree shapes hold up the spectacular roof. The architecture is extremely creative, and wonders lie around every corner.


I visited a new museum under the church. At the entrance, it had a Gaudi quote:

First there must be love.

Then there must be technique.

This quote sums up La Sagrada Familia. Gaudi used complex mathematics to plan his constructions. He was a master of technique. But he knew that it all meant nothing without love.

In writing about educational research, I try to remind my readers of this from time to time. There is much technique to master in creating educational programs, evaluating them, and fairly summarizing their effects. There is even more technique in implementing proven programs in schools and classrooms, and in creating policies to support use of proven programs. But what Gaudi reminds us of is just as essential in our field as it was in his. We must care about technique because we care about children. Caring about technique just for its own sake is of little value. Too many children in our schools are failing to learn adequately. We cannot say, “That’s not my problem, I’m a statistician,” or “that’s not my problem, I’m a policymaker,” or “that’s not my problem, I’m an economist.” If we love children and we know that our research can help them, then it’s all of our problems. All of us go into education to solve real problems in real classrooms. That’s the structure we are all building together over many years. Building this structure takes technique, and the skilled efforts of many researchers, developers, statisticians, superintendents, principals, and teachers.

Each of us brings his or her own skills and efforts to this task. None of us will live to see our structure completed, because education keeps growing in techniques and capability. But as Gaudi reminds us, it’s useful to stop from time to time and remember why we do what we do, and for whom.

Photo credit: By Txllxt TxllxT [CC BY-SA 4.0  (https://creativecommons.org/licenses/by-sa/4.0)], from Wikimedia Commons

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.

Teachers’ Crucial Role in School Health

These days, many schools are becoming “community schools,” or centering on the “whole child.”  A focus of these efforts is often on physical health, especially vision and hearing. As readers of this blog may know, our group at Johns Hopkins School of Education is collaborating on creating, evaluating, and disseminating a strategy, called Vision for Baltimore, to provide every Baltimore child in grades PK to 8 who needs them with eyeglasses. Our partners are the Johns Hopkins Hospital’s Wilmer Eye Institute, the Baltimore City Schools, the Baltimore City Health Department, Vision to Learn, a philanthropy that provides vision vans to do vision testing, and Warby Parker, which provides children with free eyeglasses.  We are two years into the project, and we are learning a lot.

The most important news is this:  you cannot hope to solve the substantial problem of disadvantaged children who need glasses but don’t have them by just providing vision testing and glasses.  There are too many steps to the solution.  If things go wrong and are not corrected at any step, children end up without glasses.   Children need to be screened, then (in most places) they need parent permission, then they need to be tested, then they need to get correct and attractive glasses, then they have to wear them every day as needed, and then they have to replace them if they are lost or broken.


School of Education graduate student Amanda Inns is writing her dissertation on many of these issues. By listening to teachers, learning from our partners, and trial and error, Amanda, ophthalmologist Megan Collins, Lead School Vision Advocate Christine Levy, and others involved in the project came up with practical solutions to a number of problems. I’ll tell you about them in a moment, but here’s the overarching discovery that Amanda reports:

Nothing can stop a motivated and informed teacher.

What Amanda found out is that all aspects of the vision program tended to work when teachers and principals were engaged and empowered to try to ensure that all children who needed glasses got them, and they tended not to work if teachers were not involved.  A moment’s reflection would tell you why.  Unlike anyone else, teachers see kids every day. Unlike anyone else, they are likely to have good relationships with parents.  In a city like Baltimore, parents may not answer calls from most people in their child’s school, and even less anyone in any other city agency.  But they will answer their own child’s teacher. In fact, the teacher may be the only person in the school, or indeed in the entire city, who knows the parents’ real, current phone number.

In places like Baltimore, many parents do not trust most city institutions. But if they trust anyone, it’s their own child’s teacher.

Cost-effective citywide systems are needed to solve widespread health problems, such as vision (about 30% of Baltimore children need glasses, and few had them before Vision for Baltimore began).  Building such systems should start, we’ve learned, with the question of how teachers can be enabled and supported to ensure that services are actually reaching children and parents. Then you have to work backward to fill in the rest of the system.

Obviously, teachers cannot do it alone. In Vision for Baltimore, the Health Department expanded its screening to include all grades, not just state-mandated grades (PK, 1, 8, and new entrants).  Vision to Learn’s vision vans and vision professionals are extremely effective at providing testing. Free eyeglasses, or ones paid for by Medicaid, are essential. The fact that kids (and teachers) love Warby Parker glasses is of no small consequence. School nurses and parent coordinators play a key role across all health issues, not just vision. But even with these services, universal provision of eyeglasses to students who need them, long-term use, and replacement of lost glasses, are still not guaranteed.

Our basic approach is to provide services and incentives to help teachers be as effective as possible in supporting vision health, using their special position to solve key problems. We hired three School Vision Advocates (SVAs) to work with about 43 schools entering the vision system each year. The SVAs work with teachers and principals to jointly plan how to ensure that all students who need them will get, use, and maintain their glasses. They interact with principals and staff members to build excitement about eyeglasses, offering posters to place around each school. They organize data to make it easy for teachers to know which students need glasses, and which students still need parent permission forms. They provide fun prizes, $20 worth of school supplies, to all teachers in schools in which 80% of parents sent in their forms.  They get to know school office staff, also critical to such efforts.  They listen to teachers and get their ideas about how to adapt their approaches to the school’s needs.  They do observations in classes to see what percentage of students are wearing their glasses. They arrange to replace lost or broken glasses.  They advocate for the program in the district office, and find ways to get the superintendent and other district leaders to show support for the teachers’ activities directed toward vision.

Amanda’s research found that introducing SVAs into schools had substantial impacts on rates of parent permission, and adding the school prizes added another substantial amount. Many students are wearing their glasses. There is still more to do to get to 100%, but the schools have made unprecedented gains.

Urban teachers are very busy, and adding vision to their list of responsibilities can only work if the teachers see the value, feel respected and engaged, and have help in doing their part. What Amanda’s research illustrates is how modest investments in friendly and capable people targeting high-leverage activities can make a big difference across an entire city.

Ensuring that all students have good vision is critical, and a hit-or-miss strategy is not sufficient. Schools need systems to bring cost-effective services to thousands of kids who need help with health issues that affect very large numbers, such as vision, hearing, and asthma. Teachers still must focus first on their roles as instructors, but with help, they can also provide essential assistance to build the health of their students.  No system to solve health problems that require daily, long-term monitoring of children’s behavior can work at this scale in urban schools without engaging teachers.

Photo credit: By SSgt Sara Csurilla [Public domain], via Wikimedia Commons

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.

“But It Worked in the Lab!” How Lab Research Misleads Educators

In researching John Hattie’s meta-meta analyses, and digging into the original studies, I discovered one underlying factor that more than anything explains why he consistently comes up with greatly inflated effect sizes:  Most studies in the meta-analyses that he synthesizes are brief, small, artificial lab studies. And lab studies produce very large effect sizes that have little if any relevance to classroom practice.

This discovery reminds me of one of the oldest science jokes in existence: (One scientist to another): “Your treatment worked very well in practice, but how will it work in the lab?” (Or “…in theory?”)


The point of the joke, of course, is to poke fun at scientists more interested in theory than in practical impacts on real problems. Personally, I have great respect for theory and lab studies. My very first publication as a psychology undergraduate involved an experiment on rats.

Now, however, I work in a rapidly growing field that applies scientific methods to the study and improvement of classroom practice.  In our field, theory also has an important role. But lab studies?  Not so much.

A lab study in education is, in my view, any experiment that tests a treatment so brief, so small, or so artificial that it could never be used all year. Also, an evaluation of any treatment that could never be replicated, such as a technology program in which a graduate student is standing by every four students every day of the experiment, or a tutoring program in which the study author or his or her students provide the tutoring, might be considered a lab study, even if it went on for several months.

Our field exists to try to find practical solutions to practical problems in an applied discipline.  Lab studies have little importance in this process, because they are designed to eliminate all factors other than the variables of interest. A one-hour study in which children are asked to do some task under very constrained circumstances may produce very interesting findings, but cannot recommend practices for real teachers in real classrooms.  Findings of lab studies may suggest practical treatments, but by themselves they never, ever validate practices for classroom use.

Lab studies are almost invariably doomed to success. Their conditions are carefully set up to support a given theory. Because they are small, brief, and highly controlled, they produce huge effect sizes. (Because they are relatively easy and inexpensive to do, it is also very easy to discard them if they do not work out, contributing to the universally reported tendency of studies appearing in published sources to report much higher effects than reports in unpublished sources).  Lab studies are so common not only because researchers believe in them, but also because they are easy and inexpensive to do, while meaningful field experiments are difficult and expensive.   Need a publication?  Randomly assign your college sophomores to two artificial treatments and set up an experiment that cannot fail to show significant differences.  Need a dissertation topic?  Do the same in your third-grade class, or in your friend’s tenth grade English class.  Working with some undergraduates, we once did three lab studies in a single day. All were published. As with my own sophomore rat study, lab experiments are a good opportunity to learn to do research.  But that does not make them relevant to practice, even if they happen to take place in a school building.

By doing meta-analyses, or meta-meta-analyses, Hattie and others who do similar reviews obscure the fact that many and usually most of the studies they include are very brief, very small, and very artificial, and therefore produce very inflated effect sizes.  They do this by covering over the relevant information with numbers and statistics rather than information on individual studies, and by including such large numbers of studies that no one wants to dig deeper into them.  In Hattie’s case, he claims that Visible Learning meta-meta-analyses contain 52,637 individual studies.  Who wants to read 52,637 individual studies, only to find out that most are lab studies and have no direct bearing on classroom practice?  It is difficult for readers to do anything but assume that the 52,637 studies must have taken place in real classrooms, and achieved real outcomes over meaningful periods of time.  But in fact, the few that did this are overwhelmed by the thousands of lab studies that did not.

Educators have a right to data that are meaningful for the practice of education.  Anyone who recommends practices or programs for educators to use needs to be open about where that evidence comes from, so educators can judge for themselves whether or not one-hour or one-week studies under artificial conditions tell them anything about how they should teach. I think the question answers itself.

This blog was developed with support from the Laura and John Arnold Foundation. The views expressed here do not necessarily reflect those of the Foundation.