Baseline

From EvaluationWiki

The baseline is the level at which a prospective customer, whether the beneficiary of a program being evaluated, or a student in a class trying out a new approach to learning, is performing before the evaluand is introduced. (We often talk shorthand about this, saying that the baseline is the level at which the program was operating before it got going, though this is, strictly speaking, nonsense.) Since evaluators are often brought in nearer to the end of a development cycle than to its start-up, it's common for them to be unable to directly determine the true baseline, which they then have to estimate or do without, a serious weakness through no fault of the evaluator. Getting baseline data could in principle be done by the staff of the program, but since it takes substantial evaluation skill to know exactly what needs to be measured, it's better to get evaluation advice from start-up onwards.