Permanent committees carry over from one session to the next. Sometimes permanent committees are discontinued and new ones created, but they are generally long lived.
All the committees in the Senate and most of the committees in the House are focused on specific areas of public policy (like agriculture, commerce, natural resources, etc.). Additionally, the House has some committees that deal with the processes and functioning of that particular chamber (e.g., Calendars committee).
Each chamber of the Legislature has its own classification for permanent committees. The Senate rules identify two types:
Standing committees are the permanent committees of the Senate whose chairs and other members are named by the Lieutenant Governor. All of these committees deal with areas of public policy (as opposed to internal functioning of the Senate).
Special committees are essentially subcommittees of regular standing committees in the Senate that are created to study important issues (like border affairs, electric utility restructuring, or agriculture). These committees have less permanence than standing committees, but because they are responsible for areas of public policy and can carry over from one session to the next, we choose to regard them as part of the system of permanent committees.
The House has two types of committees as well:
Substantive committees are similar to standing committees in the Senate. They deal with issues of substantive public policy like energy, the environment, and insurance. The House has slightly more than twice the number of substantive committees as the Senate has standing committees. This reflects the greater number of representatives seeking a committee chair or at least membership on an important committee. Control over an area of policy exercised by each committee gives the chair and its members considerable influence.
Procedural committees are a type of permanent committee dedicated to regulating the operations and functioning of the House. Although they don't deal with the substance of public policy directly, these committees play a critical role in the legislative process. The Calendars committee, for instance, can be very influential. In the short legislative session getting an early date for consideration on the floor is critical to a bill's chances of success. As a consequence, seats on this and other procedural committees are highly coveted.
In addition to the permanent committees in both houses, there are a number of temporary committees.
Conference committees are composed of members of both chambers and are formed to resolve differences between bills that deal with the same issue passed by each house. You can imagine that even if two bills start out the same, by the time each wends its way through the tortuous processes of both houses, they will come out in quite different forms. Consequently, one last revision is conducted by a subset of legislators from both houses. The bill is returned to both houses for a final vote.
Interim committees are formed to consider bills when the legislature is not in session as a way to do preparatory work for the next session. They also may be formed to study a particular problem that has come up since the end of the last session.
Sometimes these temporary committees are formed within a single chamber, or they are formed as joint committees with members from both chambers.
Of these temporary committees, conference committees tend to be the most important in affecting legislation. Conference committees are composed of five members from each house appointed by the respective presiding officers to resolve any differences between the house and senate versions of a measure. Conference committees are formed when the originating chamber refuses to concur in changes made by the other chamber. Upon reaching an agreement, the conferees issue a conference committee report (text of a bill and required attachments) that is then considered for approval by both houses.