The evaluation design, which prescribes when and from whom to gather data, is described as significant because it can lend credibility to evaluation results. The objectives of this booklet are to aid the evaluator in: choosing a design; putting it into operation; and analyzing and reporting the data. Examples include both formative and summative…

Twelve common errors which can invalidate an otherwise sound evaluation are identified, and ways to avoid them are presented. The hazards are: (1) grade-equivalent scores; (2) inappropriate statistical adjustments with nonequivalent control groups; (3) administering norm-referenced tests at inappropriate times of the school year; (4) inappropriate…