Primary data is when the data is gathered immediately after something happened but secondary data is gathered after a while it happened.
Yes, effective leadership involves chosing the right style for the situation. Every leadership situation has different variables and followers. Think of a coach that fails with one team and wins with another.
The reason why the governments used this kind of contract is because they are trying to protect the national security in which could be potentially harm with some instances if they are not careful enough. They are using these in order to prevent such things to occur and to secure their national security.