The initial quality measurements used to determine if a variance has occurred is known as the:

A Quality checklist is a structured tool for verifying that a set of required steps or items have been performed or are present, not the initial measurement for variance detection.

In project management, a baseline is the approved version of a work product, plan, or specification that serves as a reference point for comparing against actual performance. It is the initial set of measurements or the established plan against which variances are measured.

Quality metrics are specific measures used to quantify quality attributes, but the baseline is the approved set of these measurements against which current performance is compared.

A Control limit (upper or lower) defines the acceptable range of variation in a process, typically derived from statistical process control, and while related to variance, the baseline is the target or starting point itself.