Case Study: Human Error Bias Breakdown

Scenario Overview

A pharmaceutical manufacturer experiences a recurring deviation involving incomplete batch record entries.

Over a twelve-month period, quality review identifies:

• missing initials

• incomplete data fields

• delayed entries

• occasional correction errors

Each event is investigated individually.

The most common root cause conclusion is:

Operator failed to follow procedure.

Corrective actions typically include:

• retraining

• procedural review

• supervisor discussion

The deviations continue to recur.

Eventually, management initiates a broader review to determine why repeated corrective actions have failed to prevent recurrence.

Initial Investigation Conclusion

The investigation teams consistently identify:

• operator error

• procedural noncompliance

• failure to follow instructions

The conclusions appear reasonable because:

• the operator completed the activity

• the error occurred during execution

• the SOP requirements were clearly documented

As a result, investigations close quickly.

CAPAs are implemented.

Records are completed.

The problem appears resolved.

The First Warning Sign

Over time, quality personnel notice an unusual pattern.

Different operators are involved in the deviations.

The affected shifts vary.

The errors occur across multiple products.

The recurring factor is not the individual operator.

The recurring factor is the process itself.

This observation raises an important question:

If different people continue making similar mistakes, is the problem really individual performance?

Expanding the Investigation

The organization performs a broader review using QRM principles.

The team evaluates potential contributing factors including:

• procedure design

• form design

• workload

• staffing levels

• review practices

• training effectiveness

• environmental conditions

The objective is not to excuse human error.

The objective is to understand why the error continues recurring.

Evaluating Failure Pathways

The review identifies several potential contributors.

Potential Contributor	Observation
SOP complexity	Multiple sections interpreted inconsistently
Form design	Required fields easily overlooked
Workload	Documentation completed during busy periods
Review process	Errors often detected late
Training approach	Focused on procedure content rather than practical execution

The analysis reveals that multiple conditions influence the likelihood of error.

Where Human Error Bias Appeared

The organization had unconsciously adopted a simple assumption:

If a person made the mistake, the person is the root cause.

This assumption created several problems.

Investigations stopped once human error was identified.

Alternative contributors received limited evaluation.

Corrective actions focused primarily on retraining.

The broader system remained unchanged.

As discussed in Applying FMEA During Investigations, focusing too quickly on one explanation can reduce visibility of other meaningful failure pathways.

Detectability Was Also Weak

The review identifies another issue.

Many documentation errors were detected only during final quality review.

This means:

• errors remained active for extended periods

• immediate correction opportunities were missed

• trends developed before becoming visible

Delayed visibility reduces confidence in the effectiveness of operational controls.

The problem was not simply error occurrence.

The problem was also weak detection capability.

CAPA Effectiveness Review

The team reviews previous corrective actions.

Most CAPAs consisted of:

• retraining

• documented coaching

• management reminders

Few actions addressed:

• form usability

• process design

• workload management

• review timing

• procedural clarity

This explains why recurrence remained visible despite multiple completed CAPAs.

As discussed in Risk-Based CAPA, corrective actions should reduce operational exposure rather than simply respond to individual events.

The Revised Root Cause Understanding

The organization ultimately concludes that the recurring deviations result from a combination of factors:

• overly complex documentation workflow

• form design weaknesses

• inconsistent execution conditions

• delayed detection mechanisms

• limited effectiveness of previous corrective actions

Human error remained part of the event.

However, it was no longer viewed as the complete explanation.

The system surrounding the error became visible.

Corrective Actions Implemented

The organization implements:

• simplified forms

• revised documentation workflow

• targeted procedural revisions

• earlier review checkpoints

• effectiveness monitoring

• focused practical training

The objective shifts from correcting individuals to improving the reliability of the process itself.

Outcome

Over the following year:

• documentation deviations decline significantly

• repeat observations decrease

• review efficiency improves

• CAPA recurrence drops

No single change eliminates all errors.

However, overall system reliability improves substantially.

Lessons Learned

Several lessons emerge:

• Human error is often an event description rather than a root cause.

• Similar errors across multiple individuals may indicate system weakness.

• Detectability influences confidence in control effectiveness.

• Retraining alone rarely resolves recurring process failures.

• CAPAs should address operational conditions as well as personnel behavior.

Most importantly:

The organization improved performance when it shifted attention from who made the mistake to why the system allowed the mistake to recur.

What Good Looks Like

A mature investigation process:

• evaluates system contributors alongside human actions

• avoids premature root cause conclusions

• assesses detectability limitations

• reviews recurrence trends

• challenges assumptions about human performance

Within Quality Risk Management(ICH Q9), the objective is not simply identifying who was involved in a failure.

The objective is understanding the conditions that made the failure possible.

Operational Perspective

Many recurring quality problems are attributed to human error because human actions are the most visible part of the event.

However, visible actions are not always the primary driver of risk.

The strongest investigations evaluate whether procedures, forms, workloads, review processes, and oversight systems are creating conditions where similar failures become likely.

When organizations focus exclusively on the individual, they often miss the opportunity to improve the system.

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