Positions in Quill are the system on which the Purge is based, and part of the larger hierarchy of Quill.
The three positions in Quill where presumably created by former High Priest Justine when she instigated the Purge.
Infractions are any sign of creativity. Examples include drawing, singing, and even boasting. An Infraction is reported to the Governors or the High Priest, and will result in the one reported being Purged.
There are three positions in Quill's society.
Wanteds are the highest rank. They are people that are considered valuable by the Governors of Quill and the High Priest, chosen for their intelligence and strength. In order to be a Wanted, one must have never had an Infraction. After the Purge, Wanteds are sent to Quill's University. Only a Wanted can become a Governor, or eventually even the High Priest. Wanteds are not Purged.
Necessaries are the second highest rank. They are the people that the Governors and High Priest deem necessary for Quill's success. While they are not sent to their deaths, Necessaries are treated badly and used as slaves in Quill. A person is considered Necessary when they have not had an Infraction, but have none of the qualities that would make them a Wanted. Necessaries have no career choice. Necessaries are not Purged.
Unwanteds are the third and lowest rank. They are people that the Governors and High Priest have received reports of Infractions that they have supposedly committed. They are Purged and sent to their deaths, as the former High Priest Justine considered creativity to be a sign of weakness. Any couple in Quill that produces two Unwanted children is considered lowly, and prevented from producing any more children.