An example of a quantitative observation is measuring the surface of an oil painting and finding its dimensions to be 12 inches by 12 inches. A quantitative observation occurs when a researcher takes a measurement that is recorded in an objective number of units.
Quantitative observations are so called because they are observations that can be quantified; that is, that they can be represented by numbers. This is contrasted with qualitative observations, which are subjective observations based on descriptive information. An example of a qualitative observation is someone remarking that a painting is beautiful, or that it has a musty odor to it.