A multi-center study is one which is conducted at more than one center. A clinical research center may encompass one or more physical locations where the clinical study is being conducted — i.e., where study participants are recruited, and/or are intervened upon and/or have outcomes assessed under a single protocol – as long as all locations are under the overall direction of a single investigator. A study will not be considered to involve multiple centers if participant recruitment occurs at more than one site in a geographic area, but all interventions and/or outcomes assessments are performed by a single study team. A data coordinating center is not considered a clinical research center.