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Does hair length affect Metallica's songwriting?

The members of Metallica have changed their hair style with each passing album, sometimes chopping off a good foot of hair between album cycles. Since I had a lot of free time on my hands this weekend, I decided to plot the bands average hair length on a graph and compare it to the average critics review score. From the bands early days with near glam metal hair to it's shortened cuts in the 90's, it appears that Metallica's hair has expressed it's music throughout the years.

Looking at the results, it would be a safe bet to figure out their hair length while writing/recording and see if it will be an album worth picking up.