After nearly a century of industrial use, the PID controller remains the workhorse of process automation. It regulates temperatures, flows, levels, pressures and more across virtually every unit operation in a production plant. What’s more, it does so continuously, invisibly and without much fanfare. Distributed control systems have grown more sophisticated, advanced process control and AI-driven orchestration layers have entered the conversation, and historians now capture more data than ever before. Yet none of those advancements matter if a plant’s base layer of regulatory control is not performing as designed. Advanced control systems cannot optimize their way around a poorly tuned loop; they can only optimize on top of a stable one. In that sense, the PID controller is not simply a legacy technology waiting to be replaced. It is the foundation on which everything else depends.
What has been missing for decades is not better tuning theory or more sophisticated diagnostics — industry has no shortage of either. What has been missing is a clear, credible line from loop performance to production and financial outcomes. Process engineers have long known intuitively that a poorly performing controller costs money whether in the form of wasted energy, off-spec product, excess variability,or unplanned downtime. But intuition does not win capital projects, and it does not persuade a plant manager to prioritize instrumentation and tuning work over the dozen other line items competing for limited resources. The industry has needed a metric that both control engineers and plant leadership can understand and act upon.
Overall Controller Effectiveness (OCE) has emerged as a promising answer. Modeled on the well-established Overall Equipment Effectiveness (OEE) framework used throughout discrete manufacturing, OCE evaluates PID performance across three familiar dimensions – Availability, Performance and Quality – and it rolls them into a single, normalized score. The appeal of OCE is not its novelty. Rather, like OEE, it is the ability to translate loop attributes into a singular performance value. OEE already speaks the language of plant management and corporate leadership. By applying the same structure to regulatory control, OCE gives process engineers a way to communicate loop health in terms that resonate beyond the control room, and it gives leadership a way to benchmark performance at the loop, unit operation and plant level using one consistent number rather than a scattered collection of technical statistics.
Performance benchmarking is only as credible as the data behind it. To that end, controller data from tens of thousands of PID loops spanning nearly 200 production facilities from across a wide range of industries – Pulp & Paper, Oil & Gas, Chemicals, Food & Beverage, Mining and more – have been analyzed. The associated research provides something that the process industries has lacked: a statistically meaningful sample of real-world PID loops, operating under real-world conditions, large enough to support genuine benchmarking rather than just anecdotes. It is this dataset that has anchored research into OCE and into the broader question of what "good" control actually looks like across an industrial population, not just within a single facility. That intelligence is now being applied to answer questions about the relationship between control loop performance and financial outcomes – the dollars and cents the drive decisions.
The results have been something of a wake-up call. Loops that plant personnel assumed were performing well are often found operating at a fraction of their potential — whether saturated, running in the wrong mode or failing to track their targets. Making the performance gap visible, and expressing it as a single benchmarkable score, is precisely the contribution OCE is designed to make: a bridge between a technical diagnosis and a business conversation. For sure, the PID controller has earned its place at the center of process manufacturing, and it is past time that the PID’s performance has earned an equally central place in financial conversations. OCE serves a meaningful step in that direction – and there is more to come.
Join me as I explore these ideas in greater depth at the ISA Automation Summit & Expo, taking place Sept. 27–29, 2026, at the Walt Disney World Swan and Dolphin in Lake Buena Vista, Florida. It's a conversation worth being part of.
