As noted previously, a clearly defined code type is indicated by both a high elevation and either single scales, which are elevated with no other "competing" scale elevations (so-called spike profiles), or clear code types in which the elevated scales in the code types similarly do not have competing scales that are close to the degree of elevations of the scales in the code. Well-defined elevations indicate greater validity of the relevant descriptors (McNulty et al., 1998). In addition, they are more likely to be stable over time (high test-retest reliability).