What's "the Commission"?

"The commission" is the "trusted third party mentioned above”  In the case of the Facebook partnership, the commission is composed of (a) Gary King and Nathaniel Persily as co-chairs, acting like editors of a scholarly journal and (b) other members, acting like members of the journal's editorial board, but organized into methodological, substantive and regional committees. Different subsets of members (as needed, cross-cutting the committee structure) sign one of three levels of confidentiality agreement, with only the most restrictive of which has privileged access to proprietary information at Facebook and, as a result, foregoes grant applications and publication without pre-approval.

The commission is a unified structure and so it (although not every one of its members) has full access to the necessary datasets and information at Facebook needed to conduct research. The decision-making structure ensures that "the commission" can access whatever information it needs without unduly burdening its members or creating a security risk by having every single member access proprietary or privileged information that they don't necessarily need for a particular decision or analysis.