Empirical Process Control

concept
empirical-process-controlfeedback-loopsscrumagile

Empirical process control (EPC) is the practice of executing a small part of a plan, getting feedback on the result, and adapting the remaining plan. It rests on three pillars: transparency, inspection, and adaptation (bib).

Defined vs empirical process control

Defined process control (DPC) — “plan the work, then work the plan” — suits contexts where objectives, methods, and domain understanding remain stable throughout (e.g. bridge construction). Empirical process control suits contexts where the problem domain evolves rapidly and the definition of value may shift day by day.

The distinction maps to the knowledge base’s framing of open-loop vs closed-loop systems: DPC is open-loop (execute the plan without re-checking), EPC is closed-loop (execute, measure, adjust).

Three pillars

  1. Transparency — the system’s state must be visible to those inspecting it. Maps to observability in control theory.
  2. Inspection — regularly compare actual state against the goal. The comparator function.
  3. Adaptation — adjust the plan, process, or product based on what is observed. The effector/actuator.

The user’s xettel notes that empirical process control IS feedback control applied to work processes.

Implementation in Scrum

Scrum formalizes EPC into three explicit inspect-and-adapt loops, each with its own focus and accountable role:

  1. Product loop (Sprint Review) — inspect completed features, adapt the Product Backlog. Responsibility: Product Owner.
  2. Sprint loop (daily self-management) — inspect progress toward Sprint Goal, adapt the sprint plan. Responsibility: Developers.
  3. Team loop (Retrospective) — inspect team practices, adapt the process. Responsibility: Scrum Master.

Each fires at least once per sprint, making Scrum a multi-frequency closed-loop system.

Connection to feedback control

EPC is feedback control applied to work processes. The parallels are structural: a reference signal (sprint goal / product vision), a sensor (transparency), a comparator (inspection), and an effector (adaptation). What makes it “agile” is the short cycle time — the loop runs every sprint rather than every quarter (OKR) or every project phase (waterfall).

See also