What scale of measurement classifies and assigns numerals but does not distinguish size or amount?

The nominal scale is a level of measurement that classifies data into distinct categories without any order or ranking among them. It assigns numerals or labels to identify different groups but does not provide any indication of the size or amount of differences between these categories. Thus, each category is treated as equal in value, making nominal measurement suitable for qualitative data where the focus is on identifying and labeling rather than quantifying.

For example, in a study categorizing participants by their favorite colors, each color can be assigned a number (e.g., red = 1, blue = 2) but does not imply that one color is "greater" or "lesser" than another. Consequently, the nominal scale is vital in various fields, including social sciences and market research, where classifications are essential without the need for quantitative comparisons.