Although ‘variable data’ indicates values that change over time, this term is often used to describe numerical measurements taken on a continuous scale, such as time, temperature, weight, height, voltage etc. Intervals on the continuous scale are infinitely divisible into smaller and smaller Units.
For instance, even though the cycle time for shipping a product may be measured in whole days, it could be further sub-divided into fractions of a day, such as 1.5 days, without losing meaning.
Continuous measurements provide the greatest possible information (within the boundaries of measurement device resolution) because values are represented directly instead of being grouped together into broad categories. As a result, analyses based on continuous data tend to be more powerful than those based on categorical data.