While pharmaceutical companies are ultimately responsible for assuring the control and review of outsourced activities and the quality of purchased materials, many struggle with supply chain visibility due to the complexity of multi-tiered supply chains, inadequate IT systems, limited experience, and resource constraints. The supply chain has gotten increasingly complicated over the past decade. The complexity arises from the entrance of vendors from many countries into the marketplace; vendors that previously played a small or limited role. Mergers and acquisitions have also complicated the supply chain, particularly around quality.