Subsequent reports of a State party that has already presented its Initial Report are called periodic reports. These are submitted every four years thereafter.
At this stage a set of questions is prepared by a smaller group of experts called the pre-sessional working group. They will meet at the session prior to the actual session in which the State party will be reviewed, in order to elicit clarifications or to ask for more information if the report is not comprehensive enough.
Requests for clarifications and more information are then sent to the government and they have to submit written replies. The oral review takes only one day at which time the written replies are considered.