BAVSocial measures social media's influence on longterm brand performance.
Burger brand has moved away from raunchy spots.
It includes a joint venture to form Mother Shanghai.
Havas formerly handled the account.
The agency will focus on brand development.
Goodby Silverstein & Partners handles creative for the brand.
OMD has held the business since 2003.
It is unclear whether incumbent KBS will defend.
It won the assignment without a review.
Chain spent $90 million on paid media last year.