 Under the uncertainty-based conception, imprecision is a special type of inaccuracy. For example, the inaccuracy of weight measurements is the breadth of spread of values that are reasonably attributed to the object’s weight given the indications of the balance and available background knowledge about the way the balance works and the standard weights used. The imprecision of these measurements is the component of inaccuracy arising from uncontrolled variations to the indications of the balance over repeated trials. Other sources of inaccuracy besides imprecision include imperfect corrections to systematic errors, inaccurately known physical constants, and vague measurand definitions, among others (see  Section 7.1).