Swallowing Camels


The New Testament contains a wonderful quotation that I use often, because it unfortunately applies to so much of educational research:

Ye blind guides, which strain at a gnat, and swallow a camel (Matthew 23:24).

The point of the quotation, of course, is that we are often fastidious about minor (research) sins while readily accepting major ones.

In educational research, “swallowing camels” applies to studies accepted in top journals or by the What Works Clearinghouse (WWC) despite substantial flaws that lead to major bias, such as use of measures slanted toward the experimental group, or measures administered and scored by the teachers who implemented the treatment. “Straining at gnats” applies to concerns that, while worth attending to, have little potential for bias, yet are often reasons for rejection by journals or downgrading by the WWC. For example, our profession considers p<.05 to indicate statistical significance, while p<.051 should never be mentioned in polite company.

As my faithful readers know, I have written a series of blogs on problems with policies of the What Works Clearinghouse, such as acceptance of researcher/developer-made measuresfailure to weight by sample size, use of “substantively important but not statistically significant” as a qualifying criterion, and several others. However, in this blog, I wanted to share with you some of the very worst, most egregious examples of studies that should never have seen the light of day, yet were accepted by the WWC and remain in it to this day. Accepting the WWC as gospel means swallowing these enormous and ugly camels, and I wanted to make sure that those who use the WWC at least think before they gulp.

Camel #1: DaisyQuest. DaisyQuest is a computer-based program for teaching phonological awareness to children in pre-K to Grade 1. The WWC gives DaisyQuest its highest rating, “positive,” for alphabetics, and ranks it eighth among literacy programs for grades pre-K to 1.

There were four studies of DaisyQuest accepted by the WWC. In each, half of the students received DaisyQuest in groups of 3-4, working with an experimenter. In two of the studies, control students never had their hands on a computer before they took the final tests on a computer. In the other two, control students used math software, so they at least got some experience with computers. The outcome tests were all made by the experimenters and all were closely aligned with the content of the software, with the exception of two Woodcock scales used in one of the studies. All studies used a measure called “Undersea Challenge” that closely resembled the DaisyQuest game format and was taken on the computer. All four studies also used the other researcher-made measures. None of the Woodcock measures showed statistically significant differences, but the researcher-made measures, especially Undersea Challenge and other specific tests of phonemic awareness, segmenting, and blending, did show substantial significant differences.

Recall that in the mid-to late-1990s, when the studies were done, students in preschool and kindergarten were unlikely to be getting any systematic teaching of phonemic awareness. So there is no reason to expect the control students to be learning anything that was tested on the posttests, and it is not surprising that effect sizes averaged +0.62. In the two studies in which control students had never touched a computer, effect sizes were +0.90 and +0.89, respectively.

Camel #2: Brady (1990) study of Reciprocal Teaching

Reciprocal Teaching is a program that teaches students comprehension skills, mostly using science and social studies texts. A 1990 dissertation by P.L. Brady evaluated Reciprocal Teaching in one school, in grades 5-8. The study involved only 12 students, randomly assigned to Reciprocal Teaching or control conditions. The one experimental class was taught by…wait for it…P.L. Brady. The measures included science, social studies, and daily comprehension tests related to the content taught in Reciprocal Teaching but not the control group. They were created and scored by…(you guessed it) P.L. Brady. There were also two Gates-MacGinitie scales, but they had effect sizes much smaller than the researcher-made (and –scored) tests. The Brady study met WWC standards for “potentially positive” because it had a mean effect size of more than +0.25 but was not statistically significant.

Reading Recovery is a one-to-one tutoring program for first graders that has a strong tradition of rigorous research, including a recent large-scale study by May et al. (2016). However, one of the earlier studies of Reading Recovery, by Schwartz (2005), is hard to swallow, so to speak.

In this study, 47 Reading Recovery (RR) teachers across 14 states were asked by e-mail to choose two very similar, low-achieving first graders at the beginning of the year. One student was randomly assigned to receive RR, and one was assigned to the control group, to receive RR in the second semester.

Both students were pre- and posttested on the Observation Survey, a set of measures made by Marie Clay, the developer of RR. In addition, students were tested on Degrees of Reading Power, a standardized test.

The problems with this study mostly have to do with the fact that the teachers who administered pre- and posttests were the very same teachers who provided the tutoring. No researcher or independent tester ever visited the schools. Teachers obviously knew the child they personally tutored. I’m sure the teachers were honest and wanted to be accurate. However, they would have had a strong motivation to see that the outcomes looked good, because they could be seen as evaluations of their own tutoring, and could have had consequences for continuation of the program in their schools.

Most Observation Survey scales involve difficult judgments, so it’s easy to see how teachers’ ratings could be affected by their belief in Reading Recovery.

Further, ten of the 47 teachers never submitted any data. This is a very high rate of attrition within a single school year (21%). Could some teachers, fully aware of their students’ less-than-expected scores, have made some excuse and withheld their data? We’ll never know.

Also recall that most of the tests used in this study were from the Observation Survey made by Clay, which had effect sizes ranging up to +2.49 (!!!). However, on the independent Degrees of Reading Power, the non-significant effect size was only +0.14.

It is important to note that across these “camel” studies, all except Brady (1990) were published. So it was not only the WWC that was taken in.

These “camel” studies are far from unique, and they may not even be the very worst to be swallowed whole by the WWC. But they do give readers an idea of the depth of the problem. No researcher I know of would knowingly accept an experiment in which the control group had never used the equipment on which they were to be posttested, or one with 12 students in which the 6 experimentals were taught by the experimenter, or in which the teachers who tutored students also individually administered the posttests to experimentals and controls. Yet somehow, WWC standards and procedures led the WWC to accept these studies. Swallowing these camels should have caused the WWC a stomach ache of biblical proportions.



Brady, P. L. (1990). Improving the reading comprehension of middle school students through reciprocal teaching and semantic mapping and strategies. Dissertation Abstracts International, 52 (03A), 230-860.

May, H., Sirinades, P., Gray, A., & Goldsworthy, H. (2016). Reading Recovery: An evaluation of the four-year i3 scale-up. Newark, DE: University of Delaware, Center for Research in Education and Social Policy.

Schwartz, R. M. (2005). Literacy learning of at-risk first grade students in the Reading Recovery early intervention. Journal of Educational Psychology, 97 (2), 257-267.

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.


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