High Reliability Fundamentals: A New Way of Thinking

PRINCIPLES OF HIGH RELIABILITY

An important concept in human performance literature is captured in the performance improvement forumla: Re + Mc → ØE. In plain English, reducing errors (Re) coupled with managing controls (Mc) leads to zero significant events (ØE). (see the DOE Human Performance Improvement Handbook, Vol. 1, pg. 1-16. This siimple, common sense formula is very appealing and useful to most people. However, to the mathematically inclined using even simple mathematical symbols implies a prceision that doe snot exist and is therefore confusing. Instead of facilitating learning as intended, the formula becomes a barrier.

The formula has two characteristics that give the mathematician trouble. First, adding two terms implies they independently contribute to the result. In this case, if one succeeded in driving errors to zero, there would still be many significant events if Mc were some positive number. Instead, these terms intuitively interact. That is, errors combine with the inadequate controls to produce events. In mathematics interactive terms are multiplied (or divided). They give each other leverage or are catalysts.

Second, the term “managing controls” is counterintuitive. Intuition says that more or better managing is good, but the current formula implies that would lead to more events not fewer! How should one think about Mc if it is small? Slightly altered the meaning for the Mc term to: “maximizing control effectiveness” thereby makes large Mc very good.

Combining the two changes, an alternative performance improvement formula that may appeal to the mathematician and non-mathematician alike: Lim Re/Mc → ØE. That is, one approaches zero events by reducing errors and maximizing control effectiveness. This recognizes that errors will never be zero and that control effectiveness can never be infinite, but by making one small and the other very large one can get very close to zero (many 9s in quality-speak).

Finally, it is important to communicate that Re and Mc are actually complex, non-linear functions with multiple variables. Indeed, humans are in the loop and there are no known closed form formulas that describe human behavior. The best one can do is use heuristic tools designed to help identify and correct undersirable situations.

Extending the Concept to High Reliability Organizational (HRO) Theory

The performance improvement formula may be further enhanced using High Reliability Organization (HRO) concepts. Research on resilient performance has documented differences in the ideal work and acutual work practice, a notion referred to as a “work perception gap”— basically the difference between work as imagined as opposed to how work is actually done.¹ When the two are not aligned the resulting gap can further complicate error reduction and management control efforts thus leading to more significant events. This is a simple, but very powerful concept.

For this discussion, define Wi = work as imagined and Wd = work as done (each > 0); assume Wd can never be better than Wi (Wd ≤ Wi), so that the ratio Wd/Wi is always less than or equal to 1. Ideally, Wd/Wi would equal 1, but in the real world the ratio is going to be less than 1.

In order to be a good scaling factor in the performance improvement formula the new parameter must approach zero as it improves so it contributes to achieving zero events. A suitable parameter is then (1 – Wd/Wi). This parameter approaches zero as the work as done approaches work as imagined. Some may recognize an equivalent form is (Wi – Wd)/Wi or the difference between work as imagined and work as done scaled by the larger of the two, Wi.

This leads to proposing a new work gap scaling parameter using the form "delta W" for the work perception gap:

ΔW = (1 – Wd/Wi) = (Wi – Wd)/Wi.

The new HRO form of the performance improvement formula then becomes:

Lim (Re/Mc) ΔW → ØE.

Minimizing errors and the work perception gap while maximizing control effectiveness will significantly lower the probability of significant events.

There are two more distinctions from high reliability research that shape a formula for a strategic reliability approach; risk management and resilience. The Re expression was initially focused on the idea that with proper work design considering expertise and performance support tools, the incidence of error could be minimized. While that remains a desirable goal, the reality is that conditions are never ideal, the map is not the territory, thus there will always be a positive ΔW . The ability to notice the Δ is a function of what researchers term ‘mindfulness,’ and the ability to notice and understand is termed ‘sensemaking’. So the function of the Re term can be modified to reflect noticing and sensemaking.

The second distinction of resilience is the ability to respond to the unexpected. In complex systems circumstances sometimes come together in never before seen ways, ways that are computationally impossible to predict in design. Emergency preparedness is a classic recognition that such combinations do occur, that absolute prevention may not be possible, thus mitigation of harm becomes the driving objective. Highly reliable organizations are characterized by building the capability of resilience to detect, respond, improvise, mitigate and recover without serious harm to people, the environment or the mission. Thus a new term is added to the equation, Br for Bolstering Resilience. Bolstering is used in the sense of cushioning, supporting or adding to. As ÄW becomes small and the ability to respond to the unexpected becomes large, we may then express the strategic equation for reliability as:

(Re/Mc) (ΔW/Br) → ØE.

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