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View from the West Coast: Relevance is More Important than Methodological Purity

Bob Slavin published a blog post in which he argues that evaluation research can be damaged by using the cloud-based data routinely collected by today’s education technology (edtech). We see serious flaws with this argument and it is quite clear that he directly opposes the position we have taken in a number of papers and postings, and also discussed as part of the west coast conversations about education research policy. Namely, we’ve argued that using the usage data routinely collected by edtech can greatly improve the relevance and usefulness of evaluations.

Bob’s argument is that if you use data collected during the implementation of the program to identify students and teachers who used the product as intended, you introduce bias. The case he is concerned with is in a matched comparison study (or quasi-experiment) where the researcher has to find the right matching students or classes to the students using the edtech. The key point he makes is:

“students who used the computers [or edtech product being evaluated] were more motivated or skilled than other students in ways the pretests do not detect.”

That is, there is an unmeasured characteristic, let’s call it motivation, that both explains the student’s desire to use the product and explains why they did better on the outcome measure. Since the characteristic is not measured, you don’t know which students in the control classes have this motivation. If you select the matching students only on the basis of their having the same pretest level, demographics, and other measured characteristics but you don’t match on “motivation”, you have biased the result.

The first thing to note about this concern, is that there may not be a factor such motivation that explains both edtech usage and the favorable outcome. It is just that there is a theoretical possibility that such a variable is driving the result. The bias may or may not be there and to reject a method because there is an unverifiable possibility of bias is an extreme move.

Second, it is interesting that he uses an example that seems concrete but is not at all specific to the bias mechanism he’s worried about.

“Sometimes teachers use computer access as a reward for good work, or as an extension activity, in which case the bias is obvious.”

This isn’t a problem of an unmeasured variable at all. The problem is that the usage didn’t cause the improvement—rather, the improvement caused the usage. This would be a problem in a randomized “gold standard” experiment. The example makes it sound like the problem is “obvious” and concrete, when Bob’s concern is purely theoretical. This example is a good argument for having the kind of implementation analyses of the sort that ISTE is doing in their Edtech Advisor and Jefferson Education Exchange has embarked on.

What is most disturbing about Bob’s blog post is that he makes a statement that is not supported by the ESSA definitions or U.S. Department of Education regulations or guidance. He claims that:

“In order to reach the second level (“moderate”) of ESSA or Evidence for ESSA, a matched study must do everything a randomized study does, including emphasizing ITT [Intent To Treat, i.e., using all students in the pre-identified schools or classes where administrators intended to use the product] estimates, with the exception of randomizing at the start.”

It is true that Bob’s own site Evidence for ESSA, will not accept any study that does not follow the ITT protocol but ESSA, itself, does not require that constraint.

Essentially, Bob is throwing away relevance to school decision-makers in order to maintain an unnecessary purity of research design. School decision-makers care whether the product is likely to work with their school’s population and available resources. Can it solve their problem (e.g., reduce achievement gaps among demographic categories) if they can implement it adequately? Disallowing efficacy studies that consider compliance to a pre-specified level of usage in selecting the “treatment group” is to throw out relevance in favor or methodological purity. Yes, there is a potential for bias, which is why ESSA considers matched-comparison efficacy studies to be “moderate” evidence. But school decisions aren’t made on the basis of which product has the largest average effect when all the non-users are included. A measure of subgroup differences, when the implementation is adequate, provides more useful information.

2018-12-27

The Value of Looking at Local Results

The report we released today has an interesting history that shows the value of looking beyond the initial results of an experiment. Later this week, we are presenting a paper at AERA entitled “In School Settings, Are All RCTs Exploratory?” The findings we report from our experiment with an iPad application were part of the inspiration for this. If Riverside Unified had not looked at its own data, we would not, in the normal course of data analysis, have broken the results out by individual districts, and our conclusion would have been that there was no discernible impact of the app. We can cite many other cases where looking at subgroups leads us to conclusions different from the conclusion based on the result averaged across the whole sample. Our report on AMSTI is another case we will cite in our AERA paper.

We agree with the Institute of Education Sciences (IES) in taking a disciplined approach in requiring that researchers “call their shots” by naming the small number of outcomes considered most important in any experiment. All other questions are fine to look at but fall into the category of exploratory work. What we want to guard against, however, is the implication that answers to primary questions, which often are concerned with average impacts for the study sample as a whole, must apply to various subgroups within the sample, and therefore can be broadly generalized by practitioners, developers, and policy makers.

If we find an average impact but in exploratory analysis discover plausible, policy-relevant, and statistically strong differential effects for subgroups, then some doubt about completeness may be cast on the value of the confirmatory finding. We may not be certain of a moderator effect—for example—but once it comes to light, the value of the average impact can also be considered incomplete or misleading for practical purposes. If it is necessary to conduct an additional experiment to verify a differential subgroup impact, the same experiment may verify that the average impact is not what practitioners, developers, and policy makers should be concerned with.

In our paper at AERA, we are proposing that any result from a school-based experiment should be treated as provisional by practitioners, developers, and policy makers. The results of RCTs can be very useful, but the challenges of generalizability of the results from even the most stringently designed experiment mean that the results should be considered the basis for a hypothesis that the intervention may work under similar conditions. For a developer considering how to improve an intervention, the specific conditions under which it appeared to work or not work is the critical information to have. For a school system decision maker, the most useful pieces of information are insight into subpopulations that appear to benefit and conditions that are favorable for implementation. For those concerned with educational policy, it is often the case that conditions and interventions change and develop more rapidly than research studies can be conducted. Using available evidence may mean digging through studies that have confirmatory results in contexts similar or different from their own and examining exploratory analyses that provide useful hints as to the most productive steps to take next. The practitioner in this case is in a similar position to the researcher considering the design of the next experiment. The practitioner also has to come to a hypothesis about how things work as the basis for action.

2012-04-01

Exploration in the World of Experimental Evaluation

Our 300+ page report makes a good start. But IES, faced with limited time and resources to complete the many experiments being conducted within the Regional Education Lab system, put strict limits on the number of exploratory analyses researchers could conduct. We usually think of exploratory work as questions to follow up on puzzling or unanticipated results. However, in the case of the REL experiments, IES asked researchers to focus on a narrow set of “confirmatory” results and anything else was considered “exploratory,” even if the question was included in the original research design.

The strict IES criteria were based on the principle that when a researcher is using tests of statistical significance, the probability of erroneously concluding that there is an impact when there isn’t one increases with the frequency of the tests. In our evaluation of AMSTI, we limited ourselves to only four such “confirmatory” (i.e., not exploratory) tests of statistical significance. These were used to assess whether there was an effect on student outcomes for math problem-solving and for science, and the amount of time teachers spent on “active learning” practices in math and in science. (Technically, IES considered this two sets of two, since two were the primary student outcomes and two were the intermediate teacher outcomes.) The threshold for significance was made more stringent to keep the probability of falsely concluding that there was a difference for any of the outcomes at 5% (often expressed as p < .05).

While the logic for limiting the number of confirmatory outcomes is based on technical arguments about adjustments for multiple comparisons, the limit on the amount of exploratory work was based more on resource constraints. Researchers are notorious (and we don’t exempt ourselves) for finding more questions in any study than were originally asked. Curiosity-based exploration can indeed go on forever. In the case of our evaluation of AMSTI, however, there were a number of fundamental policy questions that were not answered either by the confirmatory or by the exploratory questions in our report. More research is needed.

Take the confirmatory finding that the program resulted in the equivalent of 28 days of additional math instruction (or technically an impact of 5% of a standard deviation). This is a testament to the hard work and ingenuity of the AMSTI team and the commitment of the school systems. From a state policy perspective, it gives a green light to continuing the initiative’s organic growth. But since all the schools in the experiment applied to join AMSTI, we don’t know what would happen if AMSTI were adopted as the state curriculum requiring schools with less interest to implement it. Our results do not generalize to that situation. Likewise, if another state with different levels of achievement or resources were to consider adopting it, we would say that our study gives good reason to try it but, to quote Lee Cronbach, a methodologist whose ideas increasingly resonate as we translate research into practice: “…positive results obtained with a new procedure for early education in one community warrant another community trying it. But instead of trusting that those results generalize, the next community needs its own local evaluation” (Cronbach, 1975, p. 125).

The explorations we conducted as part of the AMSTI evaluation did not take the usual form of deeper examinations of interesting or unexpected findings uncovered during the planned evaluation. All the reported explorations were questions posed in the original study plan. They were defined as exploratory either because they were considered of secondary interest, such as the outcome for reading, or because they were not a direct causal result of the randomization, such as the results for subgroups of students defined by different demographic categories. Nevertheless, exploration of such differences is important for understanding how and for whom AMSTI works. The overall effect, averaging across subgroups, may mask differences that are of critical importance for policy

Readers interested in the issue of subgroup differences can refer to Table 6.11. Once differences are found in groups defined in terms of individual student characteristics, our real exploration is just beginning. For example, can the difference be accounted for by other characteristics or combinations of characteristics? Is there something that differentiates the classes or schools that different students attend? Such questions begin to probe additional factors that can potentially be addressed in the program or its implementation. In any case, the report just released is not the “final report.” There is still a lot of work necessary to understand how any program of this sort can continue to be improved.

2012-02-14

District Data Study: Empirical’s Newest Research Product

Empirical Education introduces its newest offer: District Data StudyTM. Aimed at providing evidence of effectiveness, District Data Study assists vendors in conducting quantitative case studies using historical data from schools and districts currently engaged in a specific educational program.

There are two basic questions that can be cost-effectively answered given the available data.

  1. Are the outcomes (behavioral or academic) for students in schools that use the program better than outcomes of comparable students in schools not (or before) using the program?

  2. Is the amount of program usage associated with differences in outcomes?

The data studies result in concise reports on measurable academic and behavioral outcomes using appropriate statistical analyses of customer data from implementation of the educational product or program. District Data Study is built on efficient procedures and engineering infrastructure that can be applied to individual districts already piloting a program or veteran clients with longstanding implementation.

2011-11-20

Research: From NCLB to Obama’s Blueprint for ESEA

We can finally put “Scientifically Based Research” to rest. The term that appeared more than 100 times in NCLB appears zero times in the Obama administration’s Blueprint for Reform, which is the document outlining its approach to the reauthorization of ESEA. The term was always an awkward neologism, coined presumably to avoid simply saying “scientific research.” It also allowed NCLB to contain an explicit definition to be enforced—a definition stipulating not just any scientific activities, but research aimed at coming to causal conclusions about the effectiveness of some product, policy, or laboratory procedure.

A side effect of the SBR focus has been the growth of a compliance mentality among both school systems and publishers. Schools needed some assurance that a product was backed by SBR before they would spend money, while textbooks were ranked in terms of the number of SBR-proven elements they contained.

Some have wondered if the scarcity of the word “research” in the new Blueprint might signal a retreat from scientific rigor and the use of research in educational decisions (see, for example, Debra Viadero’s blog). Although the approach is indeed different, the new focus makes a stronger case for research and extends its scope into decisions at all levels.

The Blueprint shifts the focus to effectiveness. The terms “effective” or “effectiveness” appear about 95 times in the document. “Evidence” appears 18 times. And the compliance mentality is specifically called out as something to eliminate.

“We will ask policymakers and educators at all levels to carefully analyze the impact of their policies, practices, and systems on student outcomes. … And across programs, we will focus less on compliance and more on enabling effective local strategies to flourish.” (p. 35)

Instead of the stiff definition of SBR, we now have a call to “policymakers and educators at all levels to carefully analyze the impact of their policies, practices, and systems on student outcomes.” Thus we have a new definition for what’s expected: carefully analyzing impact. The call does not go out to researchers per se, but to policymakers and educators at all levels. This is not a directive from the federal government to comply with the conclusions of scientists funded to conduct SBR. Instead, scientific research is everybody’s business now.

Carefully analyzing the impact of practices on student outcomes is scientific research. For example, conducting research carefully requires making sure the right comparisons are made. A study that is biased by comparing two groups with very different motivations or resources is not a careful analysis of impact. A study that simply compares the averages of two groups without any statistical calculations can mistakenly identify a difference when there is none, or vice versa. A study that takes no measure of how schools or teachers used a new practice—or that uses tests of student outcomes that don’t measure what is important—can’t be considered a careful analysis of impact. Building the capacity to use adequate study design and statistical analysis will have to be on the agenda of the ESEA if the Blueprint is followed.

Far from reducing the role of research in the U.S. education system, the Blueprint for ESEA actually advocates a radical expansion. The word “research” is used only a few times, and “science” is used only in the context of STEM education. Nonetheless, the call for widespread careful analysis of the evidence of effective practices that impact student achievement broadens the scope of research, turning all policymakers and educators into practitioners of science.

2010-03-17
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