Campbell's Law

Campbell's Law Defined

In an essay on program evaluation published in 1975, Campbell issued an important warning, since dubbed “Campbell's law” by many for its broad applicability. Campbell warned that the more value placed on simplistic measures to evaluate complex systems, the more likely those measures will corrupt and distort the very system being measured. G. Madaus and M. Clarke subsequently added that under these conditions of corruption and distortion, the resultant indicator is rendered invalid. As with Werner Heisenberg's uncertainty principle in physics, it is not just the measured system that gets distorted, but also the measure itself is rendered meaningless in the process.

Campbell's Law in Education

The current reliance on students' standardized test scores for evaluating teaching and learning is an example of Campbell's law applied to education. The theory of action undergirding the practice commonly referred to as high-stakes testing is that when faced with promising incentives (pay raise, promotion to the next grade, diploma) or threatening consequences (pay cut, loss of job, being held back in school or denied a diploma), educators and their students will become more motivated to achieve (and therefore will score higher on these tests). Applying what Campbell warned about more than 30 years ago, using test scores as the single and most important indicator of school success may lead to corruption and distortion in the process of educating our children.

There are numerous examples illustrating how overreliance on test scores influences corrupt practices such as data manipulation, instructional distortion, and curriculum narrowing to name a few. As the importance of test scores rises, so too do efforts aimed at ensuring they are favorable. Some efforts are blatant, as when low-scoring students' test results are thrown out or “accidentally” discarded; or when teachers simply correct student test errors or, as was reported in one study, fill out the test for the student. Audrey Amrein-Beardsley and colleagues recount one representative example in which a teacher administering the writing portion of Arizona's Instrument for Measuring Standards (AIMS) to her students had them line up at her desk while she corrected their work. Another teacher observed this violation of testing rules and reported it to the principal. The principal ignored the teacher's claim, and later congratulated the violating teacher because her students received scores in the 85th percentile.

Inequities Magnified

Known educational distortions as a result of high-stakes testing practices are particularly dire for students of color from low-income households, those with learning disabilities, and those for whom English is a second language (ESL). For example, Julian Vasquez Heilig and Linda Darling-Hammond found that low-income students of color (who also happened to be low scorers on tests used to evaluate schools and teachers) were held back and/or dropped out at higher rates than their higher scoring peers in one urban district in Texas. Qualitative analyses revealed that teachers and administrators were complicit in practices that led to this state of affairs because the disappearance of low-scoring students ultimately enhanced school accountability ratings. This is a pattern rather than an isolated incident, as the overreliance on test performance subjects low-scoring students to practices that often minimize their value and place in school settings.

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