I think by controlling outsourcing you intended the risks. So there are some ways or we can say risk control techniques which can be followed to prevent any loss.
Problems of loss of visibility and control during outsourcing relationships can be prevented by building strong communication channels and outsourcing management awareness within your organization. Other few strategies are:
1. Make sure to manage your outsourcing process.
2. Pick a transparent vendor with proven risk management processes.
3. Maintain constant communication.
4. Make sure your entire team knows what outsourcing entails.