Claim: Head movement occurs when the partition of a phrase moves together with all its dependents in such a manner that the entire phrase moves while phrasal movement, in contrast, occurs when just the head of a phrase moves, whereby this head leaves behind its dependents.
Evidence: Head movement, in contrast, occurs when just the head of a phrase moves, whereby this head leaves behind its dependents. 
Phrasal movement occurs when the head of a phrase moves together with all its dependents in such a manner that the entire phrase moves.