Undesirable Effects (UDEs) in the Thinking Processes lingo are effects undesirable in/for a system, a process or its stakeholders and clients. UDEs are hindrances to better throughput or performance, limiting the system’s throughput or performance at large. UDEs can be obvious problems or malfunctions.
UDEs are generally well-known by people they concern, thus these people can express and list them easily. What is not so easy is to identify the root cause of all evil.
Theory of Constraints assumes that most Undesirable Effects are the visible effects of a unique or a small number of root causes, the constraints; If the constraint can be identified and eliminated, all related UDEs will disappear. Therefore it is meaningful to focus all energy and limited resources to identify and eliminate* the constraint.
*When the constraint is a physical bottleneck, eliminating may not be possible. We speak about “elevating” the constraint in this case, meaning better using the available limited capacity and/or recovering wasted capacity and/or gaining additional capacity.
UDEs are described in a manner such as: “what causes us the more trouble is..”
UDEs are stated in full sentences in present tense and written in rounded square boxes. UDEs are the “leafs” of a Current Reality Tree, which describes all UDEs and their relationships, down to a common critical root cause or more likely a small number of critical root causes.
More about so-called “problems” and UDEs: Redefining “problem” (with Goal in mind)