Build the Job to Tolerate a Mistake

Human Performance weekly series: lesson 43 of 52.

A 5–10 minute crew discussion, plus time to verify the actual controls. The crew talk and Word version are public. Separate supervisor and attendance records are included with free Safety & Systems membership.

Why this matters

A missed cue or wrong selection can reveal a weakness in the work’s protection. Use one plausible slip to ask what prevents harm. Seek an approved improvement that reduces dependence on perfect attention while preserving every required control.

Learning objective

Trace a plausible slip to its possible exposure and identify evidence that an approved control interrupts that path.

Key hazards or failure points

A harmful outcome prevented only by memory; one confusing selection reaching dangerous equipment; assumed safeguards; a control bypassed for convenience; an improvement that creates another hazard; unsafe demonstrations.

Practical controls

• Select a consequential step and describe one plausible slip, such as choosing a similar item or missing a cue. Discuss the work conditions that make it possible without judging a person.
• Ask how the exposure could be removed or reduced through approved task or equipment design. Identify existing protection and where technical help is needed. More reminders alone may leave the same vulnerability.
• Obtain the required review. Define the control’s function, governing criteria and owner. Keep current safeguards and work restrictions effective until the approved replacement is verified.

Verify It in the Field

• On paper, trace the slip, possible exposure and protective control. Ask whether that control also depends on the same missed action. Record the assumption that needs checking; a diagram or discussion is not a functional test.
• Have the designated person compare the control with its design, manufacturer instructions or governing source. Complete only the prescribed safe inspection or test. Record criterion, method, actual result and time. Never introduce a fault or bypass protection to see what happens.
• Review the approved arrangement with affected workers from a safe position. Confirm it can be used during the relevant task stages and has not introduced another exposure. Record remaining restrictions and recheck triggers; complete all other required task checks before release.

Stop and reassess

Hold affected work when a required safeguard is absent, failed or unverified, or the proposed method depends on an unauthorized workaround. Protect people and seek the appropriate technical decision. Do not create a mistake deliberately on live equipment. Resume through the required correction, verification and authorization process.

Crew discussion questions

• Which plausible slip could expose someone here?
• What protects people if that slip occurs?
• What evidence establishes that protection without creating exposure?

For each required control, record its acceptance source and criterion, safe verification method, responsible checker, actual result and time. Use VERIFIED, HOLD/NOT VERIFIED, or N/A with a reason. A tick alone is not evidence. Complete all applicable task inspections; do not enter danger or improvise a test to fill out a form.

Leader preparation and practical detail

Two reminders may depend on one act of remembering

Illustrative situation: a task has both a briefing reminder and a nearby note, but safe execution still depends on noticing the same change at the same instant. That may be useful communication, yet it does not necessarily provide separate protection. Ask the responsible reviewer whether the exposure can be removed or controlled through an approved design or method. Do not declare a design adequate from the number of reminders or signatures.

Do not prove tolerance by creating a live mistake

The crew exercise traces a scenario on paper. Actual safeguards require the inspection and testing methods specified by their governing sources, performed by authorized or qualified people as applicable. Intentionally selecting the wrong control, defeating a guard or creating a hazardous condition is not part of this lesson. If the control’s function cannot be established with an available safe method, hold the affected reliance and obtain technical help.

Keep this separate from a general reminder to self-check

The Self-Checking lesson supports an individual’s item, action and result checks. This discussion asks how the work protects people when a plausible slip still occurs. The Hierarchy of Controls lesson helps compare stronger control options, while the broad Human Performance talk explores confusing work conditions. Use those links rather than implying that this brief exercise designs or certifies a complete error-tolerant system.

Short supervisor field check

• Specific slip and potential exposure are described without blame.
• Controls are examined for dependence on the same missed action.
• Improvement has appropriate review and governing acceptance criteria.
• Authorized safe checks establish actual protective performance.
• Usability, new hazards, remaining restrictions and release are addressed.

Confirm the relevant trained/authorized people, unresolved items, interim protection, correction owner and recheck. Record required release authority and rebrief anyone affected. The separate sheet supports these records; it does not replace a specialist inspection, permit or engineering determination.

Attendance and follow-through

Use the separate attendance sheet for participants, roles, discussion concerns, actions and late-arrival rebriefs. Attendance is not proof of competence, functioning controls or authorization to work. Keep completed records private under employer procedures.

Source acknowledgment

This resource draws on the U.S. Department of Energy’s DOE-HDBK-1028-2009, Human Performance Improvement Handbook, Volume 1 (June 2009). Todd Jerome Jenkins makes no claim of authorship or copyright ownership in the original U.S. Government work. New explanations, examples, exercises and layouts are Todd Jerome Jenkins adaptations. No endorsement by DOE or the U.S. Government is implied. Third-party material credited in the handbook remains attributed to its source; this notice does not claim rights in that material.

Source excerpt: Volume 1/VOLUME 1 CHAPTER 1 -INTRODUCTION TO HUMAN PERFORMANCE OVERVIEW.pdf; Chapter 1, printed pp. 1-19 through 1-20 (PDF pages 19–20). The June 2009 handbook supplies concepts; this lesson uses original explanations and exercises.

Technical scope and references

References reviewed October 9, 2026. DOE human-performance tools and OSHA recommended practices support preparation and discussion; they do not establish universal technical acceptance criteria. Apply the current task procedure, manufacturer instructions, permit and required competent or qualified decisions. A successful exercise does not replace required training, technical verification or work authorization.

1. DOE-HDBK-1028-2009, Volume 1 — Principles of Human Performance — June 2009, Chapter 1 printed pages 1-19–1-20: human fallibility, work conditions and proactive learning. Selected pages only; adjacent 1-18 and reference page 1-21 inspected as context. No principles list, quoted third-party passage or historical causal claim reproduced.
2. HSE — Managing Human Failures — UK regulator guidance on foreseeable errors, work conditions and error-tolerant task/equipment design; not a U.S. legal standard.
3. NIOSH — Hierarchy of Controls — April 10, 2024 guidance: prefer effective controls requiring less sustained human interaction and assess new hazards from changes.

Connect this discussion to your JHA/JSA

Use the JHA/JSA planning and field-verification worksheet to record the actual task steps, hazards, responsible roles and controls. No task-specific worked example is linked for this topic yet. Return to What Changed Today? when the plan or conditions change.

Related Todd Jerome Jenkins articles: How to Conduct a Job Safety Analysis and What Is Human and Organizational Performance?.

Related crew discussions

• Human Performance: Make the Next Step Clearer
• What Does This Control Actually Do?

Continue the weekly series

• Lesson 42: Benchmarking: Study the Practice Before Adopting It
• Lesson 44: Routine Work: Make the Critical Step Stand Out

Put one check into practice

Use the free JHA/JSA planning and field-verification worksheet to record today’s change, the required protection and the evidence needed before exposure.