Configuration management is the process of managing change in hardware, software, firmware, documentation, measurements, etc. As change requires an initial state and next state, the marking of significant states within a series of several changes becomes important. The identification of significant states within the revision history of a configuration item is the central purpose of baseline identification.
Typically, significant states are those that receive a formal approval status, either explicitly or implicitly (approval statuses may be marked individually, when such a marking has been defined, or signified merely by association to a certain baseline). Nevertheless, this approval status is usually recognized publicly. Thus, a baseline may also mark an approved configuration item, e.g. a project plan that has been signed off for execution. In a similar manner, associating multiple configuration items with such a baseline indicates those items as being approved.
Conversely, the configuration of a project often includes one or more baselines, the status of the configuration, and any metrics collected. The current configuration refers to the current status, current audit, current metrics, and latest revision of all configuration items. Similarly, but less frequently, a baseline may refer to all items associated with a specific project. This may include all revisions of all items, or only the latest revision of all items in the project, depending upon context, e.g. "the baseline of the project is proceeding as planned."
A baseline may be specialized as a specific type of baseline. Some examples include:
Baselines themselves are valued not only for their ability to identify the notable state of work product(s) but also provide particular importance in their ability to be retrieved. Once retrieved, the state of the work product(s) in that subset share the same significance in their history of changes that this significance was observed. The baseline is then regarded with poignant qualities (either favorably or disfavorably). For this reason, baseline identification, monitoring, and retrieval are critical to the success of configuration management. However, the ease of retrieving any given baseline varies according to the system employed for performing configuration management which may use a manual, automated, or hybrid approach. Once retrieved, the baseline may be compared to a particular configuration or another baseline.
Most baselines are established at a fixed point in time and serve to continue to reference that point (identification of state). However, some baselines are established to carry forward as a reference to the item itself regardless of any changes to the item. These latter baselines evolve with the progression of the work effort but continue to identify notable work products in the project.
In addition to the field of Hardware and Software Engineering, baselines can be found in Medicine (e.g. monitoring health progress), Politics (e.g. statistics), Physics & Chemistry (e.g. observations and changes), and others.