Watch the Scale Degree online guitar lesson by Brad Carlton from Guitar Lab: Boogie-Woogie
All theory is derived from the major scale (1234567). The boogie-woogie uses the 1, 5, 6, and b7 from the mixolydian mode. You will learn how to see these scale degrees on the fingerboard in this lesson. The root will usually be the lower voice and the 5, 6, b7 tones will occur in the higher voice. Because no 3rd appears in this boogie-woogie pattern, it accommodates both dominant 7 and minor 7 harmony. Blues emcompasses both tonalities so as you can see, this is a very important kingpin of rhythm guitar.