The Right Rule: Check the Conditions Before Choosing a Branch

Human Performance weekly series: lesson 45 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 familiar symptom can lead to the wrong response when today’s conditions differ. Before choosing a branch in an instruction, establish what makes that branch applicable. A correct response to a different situation can still create a hazard here.

Learning objective

Use evidence of actual conditions to select an authorized procedure branch, and refer an unresolved choice for review.

Key hazards or failure points

Similar symptoms with different causes; a remembered shortcut; an unverified starting condition; one clue treated as the whole picture; a branch chosen to keep work moving.

Practical controls

• Identify the decision point and its governing instruction. Read the complete entry conditions, including exceptions and prerequisites. Do not substitute a remembered rule for the current task requirements.
• Establish the conditions through the required safe checks before selecting the response. Keep unknown facts visible. A missing indication does not automatically mean the opposite condition exists.
• Refer an ambiguous choice to the authorized procedure or technical owner. Keep the affected step held under its safe-state arrangement. Communicate the approved selection and its basis before anyone acts.

Verify It in the Field

• Use a paper example from the applicable instruction. Have a worker point to the exact condition that selects the branch and identify where its evidence would come from. Compare the explanation with the controlled source; do not operate equipment for the exercise.
• For the actual task, the designated checker compares the required entry condition with evidence obtained by the approved method. Record the item, source criterion, actual finding and time. Check all required conditions; one matching symptom does not settle the choice.
• Ask a second crew member to explain why the selected branch applies and what would invalidate it. This discussion checks understanding, not technical qualification. Record unresolved differences and the responsible reviewer’s disposition before the affected step receives required release.

Stop and reassess

Hold when a prerequisite is unknown, the evidence supports conflicting branches or the instruction does not cover the observed condition. Maintain required protection and obtain authorized resolution. Recheck the choice if conditions change before action; do not blend steps from different branches.

Crew discussion questions

• What exact condition makes this branch applicable?
• Which required fact is still unknown?
• What change would invalidate this selection?

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

One familiar clue does not establish every entry condition

Illustrative situation: two configurations use similar labels, but an instruction contains a different branch for each configuration. A worker recognizes the label and starts with the branch used last time. Before action, compare the complete applicability conditions with the current task evidence. Do not let apparent familiarity replace identification of the actual configuration. Any necessary equipment checks remain assigned to authorized people using the approved safe method; this discussion supplies no substitute technical criteria.

An unknown condition is a separate result

A form may offer two response paths while the crew cannot establish the fact needed to choose between them. Avoid treating missing information as a negative answer. Record what is unknown, which affected step remains held and who can resolve it. The procedure owner may need to clarify applicability or provide an approved instruction. A supervisor’s confidence, a majority vote or an internet example does not establish the missing condition.

Keep this lesson focused on choosing the branch

Procedure Use covers current instructions, prerequisites and discrepancy resolution across the task. This lesson provides a narrower paper exercise at one decision point: identify the entry condition, locate its evidence and explain why an alternative does not apply. Use the actual authorized instruction, not an invented technical limit. The DOE chapter supplies historical discussion of rule selection; its tire-pressure example, incident statistics and numerical error probabilities are not used.

Short supervisor field check

• Decision point and complete entry conditions identified in the current source.
• Required evidence concerns the correct task, item and present condition.
• Designated checker records actual findings and time by the approved method.
• Unknown or conflicting conditions receive authorized disposition.
• Crew understands the selection, invalidating changes and required release.

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 2-REDUCING ERROR.pdf; Printed pp. 2-23, 2-24, 2-25. 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 — Chapter 2, printed pp. 2-23–2-25 — June 2009 conceptual source on selecting an applicable rule; old probabilities, technical examples and statistics omitted.
2. HSE — Procedures — Current UK regulator guidance on fit-for-purpose procedures, competence and procedure management; not a U.S. legal requirement.
3. OSHA — Hazard Prevention and Control — Recommended practices supporting governing source information, assigned control responsibility and implementation checks.

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

• Procedure Use: Stop When the Instructions Do Not Fit
• Assumptions: Show What Is Known and What Is Not

Continue the weekly series

• Lesson 44: Routine Work: Make the Critical Step Stand Out
• Lesson 46: Unfamiliar Work: Prepare the Question for the Right Expert

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.