Activity code represents one or more specific values that are assigned to each schedule. Each of these codes are unique and are used as a primary means of keeping track of, and making logical order of, all schedule activities. These activity codes can be comprised of all text (for example, codes could be made up of a relevant keyword such as “BUDGET”), they can be entirely numerical (examples could be “37647” or “4-5443”, or they can consist of a combination of the two (for example, “AR-564”). Utilization of activity codes also facilitates the manipulation of data, particularly when used in conjunction with electronic spreadsheet software as it allows easier filtering and reordering, Activity codes also prove useful when referring to multiple activities that may have similar sounding names, or when the names for each of these may be unwieldy or in some cases, so verbose that they are difficult to remember. In such cases, the activity code may be used almost exclusively by the project team as it is far easier to utilize and makes similar sounding titles easy to distinguish from one another.
This term is defined in the 3rd and the 4th edition of the PMBOK.