Information which uses descriptive terms to measure or classify something of interest.
The term qualitative is used to describe items in terms of quantity and in which a range numerical values are used without implying that a particular numerical value refers to a particular distinct category. However, data originally obtained as qualitative information about individual items may give rise to quantitative data if they are summarised by means of counts; and conversely, data that are originally quantitative are sometimes grouped into categories to become qualitative data.
Qualitative data describe items in terms of some quality or categorization that in some cases may be 'informal' or may use relatively ill-defined characteristics such as warmth and flavor; such subjective data are sometimes of less value to scientific research than quantitative data. However, qualitative data can include well-defined concepts such as gender, nationality or commodity type. Qualitative data can be binary (pass-fail, yes-no, etc.) or categorical data.