Analyzing Chord Progressions

The ability to analyze chord progressions to determine their key and individual chord function is essential to understanding how music works and provides a basis for writing songs and effective soloing. Additionally, learning to see chords as groups which function together will help you to break out of the habit of playing the same old chords in the same old way. As shown in the lesson on chord progressions, groups of chords generally work together. These groups (chord progressions) are fairly easy to identify once we have spent some time learning how to do so. This lesson maps out the thought process of breaking down chord progressions into their individual components to see if and how they function within a key.

The first step toward making sense of a group of chords is to determine their key. (Assuming they are all in the same key.) Before continuing, be absolutely certain that you have a firm grasp of how major scales are harmonized. This section is likely to be a little confusing at first but don't give up, it will make sense eventually and you'll wonder why it seemed so illogical. All we are trying to accomplish is to see if the chord sequence below fits within a certain key and, if so, which one.

	Analyze this chord progression to identify a common major scale or "key"

The first chord is Amin7 giving us 3 scale choices it could be derived from. (If this doesn't make sense, pay Understanding Keys a little visit.) For the moment, just know the 3 choices. We can't narrow it down fruther until we look at the rest of the chords in the progression.
The next chord D7 only resides within one major scale so, we know D7 is in the key of G major. Dominant chords are almost always the V-chord in a chord progression.
The last chord of this sequence has two possibilities. Now that we have listed all of the possibilities for all three chords, step back and look at whether or not they have any one key in common...

The Verdict...

Once all of the possibilities for each chord have been identified, the next step is to determine if they are common to one major scale. These chords may all be found within the harmonized G major scale. A min7, D 7, and G maj7 are the ii, the V, and the I in the key of G."ii-V-I" chord progressions are very common to most styles of music but are, perhaps, most common in jazz. Generally, if you encounter a minor7 chord followed by dom7, then a major7 chord, it's a safe bet that the chord progression is a ii-V-I. (If you are soloing over these chords, this means you can play the G major scale over all three chords. Keep in mind that there are other possibilities available for soloing as well. In either case analyzing the progression is the necessary first step toward making a decision about which scales to use in a solo.)