Taking these factors into account, the key to success in vetting personnel is the ability to gather information from many organizations in a way that is comfortable for each of them, and to deliver it quickly and accurately.

Several countries are already working with U.S. federal and local law enforcement agencies to provide exactly this type of capability. The key to having this type of information exchange be successful is to go beyond basic questions. Individuals who have a criminal record or are having financial difficulties will raise red flags. The key is to uncover and understand relationships they may have to other known individuals or groups -- to establish connections that are not otherwise obvious.

It is always important to note that with enough degrees of separation, everyone is related to everyone else. Therefore, accuracy in resolving entities and relationships is key to providing actionable results.

Security and intelligence analysts know to expect the unexpected. To prepare for this, law enforcement and security personnel on the ground must have ready access to knowledge about individuals they may encounter in the course of their work during the event.