NCPA - National Center for Policy Analysis

Random Assignment

May 30, 2002

The American education system has undergone many changes during the past 20 years, including experiments with whole-school reform models; the imposition of standards and high-stakes tests; the lowering of class sizes and slicing of schools into smaller, independent academies; and the explosion of charter schools and push for school vouchers.

Yet in spite of these experiments, education researchers have avoided the randomized, controlled experiments common in scientific research. Such experiments involve randomly choosing which schools, classrooms, or students will be exposed to a reform and which will be exposed to the alternative with which the reform is to be compared.

  • While the total number of articles about randomized field trials in other areas of social science research has steadily grown, the number in education research has trailed behind.
  • Of 84 program evaluations and studies planned by the Department of Education for fiscal year 2000, just one involved a randomized field trial.
  • Equally striking is that of the few randomized experiments cited above, nearly all were conducted by scholars whose training is outside the field of education.
  • The small number of randomized experiments in education may reflect not researchers' distaste for them but a simple calculation of how difficult they are to mount in the complex organizational context of schools.

It will be difficult to persuade the current community of educational evaluators to begin doing randomized experiments, say observers. Such experiments will have to be carried out by contract research firms, university faculty members with a policy science background, or by education school faculty.

Source: Thomas D. Cook, "Sciencephobia: Why Education Researchers Reject Randomized Experiments," Education Next, Fall 2001, Hoover Institution.


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