Scholars often describe the musical frameworks of blues schemes simply by length in bars and harmonic structure, an approach suggesting that musicians fix upon the same components for every scheme. I propose that the components fixed upon by musicians vary from scheme to scheme, resulting in five types of musical framework, and present five short schemes as representatives of each type.

In blues schemes, the rhythmic structure is usually among the most consistent components, after which either the harmonic or melodic structure may be more consistent, creating two broad categories: those in which the rhythmic and harmonic structures are most consistent and the discant displays more variance and substitution, and those in which the rhythmic and melodic structures are more consistent and the harmony displays more variance and substitution. In both cases, the structure of the more consistent component generally informs the choices for substitution in the less consistent.

Schemes in which the rhythm and harmony are more consistent account for three types of framework: those that support one, two, or several discants.

Schemes in which the rhythm and melody are more consistent account for two more types of framework: those in which the harmonic progression displays considerable variance and substitution, but performers nonetheless fix upon certain general requirements for it; and those in which performers do not fix upon many general requirements for the harmonic structure, but instead take their cues from the melodic structure.