The type of design that this school administrator is using is what is known as a non equivalent control group.
A non equivalent control group is one whereby a treatment group and a control group are measured and compared after getting data from both groups at the beginning and at the end of a research.
The school administrator is said to compare records of a school that has no lockers with that of a school that has lockers. Therefore the answer to this question is non equivalent control group.
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