The agency has been briefed to undertake data analysis of the carrier's frequent flyer programme, called EuroBonus, which it launched in the early 90s.
Carlson was handed the business following a competitive pitch against undisclosed agencies.
The review is intended to inform a strategy for the SAS programme, which has about 2.6m members globally, that will make it the most popular such scheme in the aviation industry.
SAS serves Copenhagen and Stockholm, as well as various cities in the US, Bangkok, Beijing and Tokyo. The airline plans to open a service to Delhi and Dubai in the near future.
EuroBonus is one of the oldest loyalty schemes in the aviation industry.