Assess the reliability of its geographical location based on the abundance of competent workforce it could provide for your business. Its methodology and infrastructure to handle conflict resolution should also be on the top of your list.
Determine its level of expertise and whether its industry knowledge would significantly contribute to how you plan to achieve your business goals.
Evaluate the cost of doing business with the outsourcing partner. Ideally, it should handle the designated tasks at a practical level without undermining the quality of service.