Quatitative data are anything that can be expressed as a number, orquantified. Examples of quantitative data are scores on achievement tests,number of hours of study, or weight of a subject. These data may berepresented by ordinal, interval or ratio scales and lend themselves to moststatistical manipulation.

Qualitative data cannot be expressed as a number. Data thatrepresent nominal scales such as gender, socieo economic status, religiouspreference are usually considered to be qualitative data.

Both types of data are validtypes of measurement, and both are used in education journals. Only quantitative datacan be analyzed statistically, and thus more rigorous assessments of the dataare possible.