The Learning TreeIncident Investigation Technique

Dr. Mark Fleming and Dylan Smibert at Saint Mary's University

Training ManualVersion 1.1

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OverviewWhy investigate incidents?

Limitations of Investigation Tools

The Learning Tree Process

Workplace Incident Example

Step by Step Implementation

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Developed in 2016 by Dr. Mark Fleming of Saint Mary’s University,Halifax, Nova Scotia, Canada. The technique was designed to beused free of charge and should not be used without permission forprofit. Manual published in September 2017.

There are many important reasons to investigate incidents.

Legal requirements

Record keeping and trend tracking

Limit legal liability

To find someone responsible

Identify direct causes and contributory factors

Raise awareness of workplace hazards

To prevent reoccurrence

The reasons listed above are understandable, but take a moment and ask yourself a couple of questions:

1. Do you have repeat incidents or events?

2. Does your current investigation technique focus on learning and improvement?

3. Are the same failures being repeatedly identified?

4. Does your investigation lead to improved organizational systems? (e.g., improved safety procedures).

Why Investigate?

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There are a lot of investigation tools and techniques available. Some tools have been developed to meet a legislative requirement, some were simply to classify and code events, and others were developed to find a “root cause.” These tools are not wrong or broken, but they do have some limitations.

For example, below is a list of potential issues with current investigation tools:

Focus solely on classification and causal factors

Too simplistic of a framework (e.g., domino theory)

Significant expertise or training is required to obtain meaningful results

The tools are proprietary and costly

Only focused on failure and weaknesses

Do not focus on learning and improvement

Do not capture cultural factors

Limitations

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An ideal investigation tool is versatile, useful, and easy to use. The ideal tool should also provide a solution to the limitations of the current tools on the market.

An ideal investigation technique would:

Focus on learning and improvement.

Be non-proprietary and free to use.

Be developed using an evidence-based systems-framework.

Be flexible, so that it can be used for a wide range of incidents, including major, minor and organizational successes (does not need to be a safety incident, it could examine a task or work process).

Require minimal training to be used effectively.

Ideal Investigation Tool

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DANGER

From Reason 1997

Engineering

and design

Management systems

and Resources

Supervision

and planning

Work practices

and leadership

Management

Supervisors

Everyone

Theoretical ModelBarrier Model

The Learning Tree Technique draws from James Reason’s “Swiss Cheese” model of incident prevention. The model suggests that there are preventative barriers (slice of cheese) that all have weaknesses (holes in cheese). Incidents occur when the holes line-up from all the barriers. Different people in the organization are responsible for each barrier. The learning Tree Technique utilizes Reason’s theory to help individuals learn about their barriers, risks and the systems which they interact.

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The Learning Tree Technique has been developed using an evidence-based framework and focuses on learning and improvement.

Developed for a wide range of incidents, including instances of safety success or the review of successful completion of a task or process.

Captures cultural components

The Learning Tree is free, non-proprietary, flexible to be used on a range of incidents, and requires minimal training to be used effectively.

The Learning TreeThe Learning Tree Technique uses a holistic team-based approach to incident investigation and safety successes. This is intended as a non-punitive technique with the goal of improvement through learning.

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Your team will create several tangible outcomes after completing The Learning Tree Technique.

Together, the group will gain a deeper understanding of the incident, the system, and the cultural factors involved.

The technique will promote accountability and action towards improvement to prevent future incidents.

The flow-chart diagram you create can be kept for reference and stored electronically for future analysis and accountability.

The Outcomes

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The process is simple. Select a group of 5-10 to participate in the investigation, and finally, work as a group through the 6-steps of the Learning Tree Technique. This is intended as a non-punitive technique with the goal of improvement through learning.

Select a group.

The LT technique is designed to be a group learning experience. Each grouping should have between 5-10 individuals. If there are more than ten interested in participating, you can create multiple groups of 5-10.

Who should be in the group? The groups can consist of employees at all positions and seniority, Joint OHS committee members, leadership, or those directly or indirectly involved in the incident. Recognize that leadership’s direct involvement in the room may bias responding and hosting separate sessions for leaders may be a solution.

The Learning Tree Process

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Select an incident or success.

Select a safety incident or successful work process that is important to the operational safety of your employees and organization.

Complete the 6-steps of the Learning Tree.

Participants identify the significant sequence of events and conditions involved in the incident, engage with the content by asking and answering questions, identify barrier failures and success, errors and their causes, cultural threats, and most importantly, produce insights and accountable actions for improvement.

The Learning Tree Process

Take an interactive and collaborative approach to the investigation.

Make sure all voices are heard and respected. The time to complete the technique depends on the

seriousness and complexity of the incident.

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The Technical Details

Electronic Version

Contact HfLab@smu.ca for the Visio template.

Open the template file “LearningTree.vsdx” in Visio. If you do not have Visio, it can be purchased from Microsoft.

The Visio file contains all of the card types, as part of the template.

Visio content can be downloaded directly into Excel or access for convenient storage.

Physical Card Version

Contact HfLab@smu.ca for printable materials.

Print each of the card types on a different coloured paper. Print eight (2-sheets) for each type of card. (.pdf)

Find a large flat surface to place and adhere the cards to. This could be a conference room table, a whiteboard or even a large piece of construction paper.

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Example IncidentIn this section, we will explain each of the 6-steps in detail using the example incident below.

This incident occurred on the date of June 26, 2012. The following information was reproduced from his witness statement collected via incident investigation at a Canadian public works department.

…Jason arrived at work at 5:45 am and conducted his regular morning routine, which consisted of the morning briefing, tool box talk, and front-end loader pre-trip process. On his way to the loader to conduct his pre-trip checks, he slipped in mud formed by the rain.

Jason was assigned to work at the transfer site (a drop-off point for household waste, which will be transferred to a larger landfill). Jason arrived at the transfer site and followed regular protocol. Jason noted it was raining heavily on the drive to the site.

Jason decides to get out of the loader to pick up some loose garbage that is scattered in front of his bucket. Jason said he engaged the handbrake before he left the cab.

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Example Incident cont.The loader was parked on a slant and slowly rolled forward pinning Jason’s legs between a cement wall and the loader bucket.

Jason called a co-worker, Eli, from his cell phone. Eli arrived 10-minutes later. He has never operated a loader before, so Jason gave him verbal instructions.

Eli was able to put the loader in reverse and move the bucket from Jason’s legs.

Jason received slight laceration and bruising on his legs. Jason did not report the incident. When asked why he said that he was embarrassed and also did not want to receive disciplinary actions.

The report was later reported by Eli 2-months later at a safety toolbox talk. An incident investigation began, and Jason was placed on suspension for 1-month for not reporting an incident…”

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The Learning Tree

Example physical version of Learning Technique

Event:Person B obtains TOP # at 00:16Includes FOLLOW BEHIND order

Event:Person A (located at mile 187.1) is added to the TOP as a separated

workgroup at 00:16

Event:Person C (located at mile 187.1) is added to the TOP as part of

the separated workgroup at 00:17

Event:Person D (located at mile 187.1) is added to the TOP as a part of the separated

workgroup

Event:Person D entered the track on a hi rail before train passed and

announced his movement

Event:Person C and Person D Free entered the track on a hi rail before

train passed

Event:Person A realizes that the hi rails have entered the track before the train has passed

Event:Person A goes to nearest vehicle and asks Person E to make an emergency radio call to stop

train

Event:Person D realizes that he has entered the track before the train has passed and gets

off track at mile 185.88

Question:What was Person B’s role in the work being completed?

Question:Why didn’t Person A apply for his own TOP?

Question:How was it possible for Person A to be added to the TOP at

the same time it was issued?

Question:How was the follow behind aspect of the TOP communicated?

Question:Who heard Person D’s announcement?

Question:What was Person D’s role in the work and relationship to

others? The TOP administrative barrier failed

Question:What information was provided in the TOP request?

Question:Why did RTC issue a follow behind TOP if work was planned

for ahead of the train?

Condition:Person A, Person C, and Person D were likely fatigued

Condition: Incident took place at night

Learning tree Analysis for Track Limits Violation

Condition:“Emergency” S&C trouble call

Question:Why was Person E at the location? What was his role in the

event?

Question:What triggered Person A to realise that the hi rails had

entered track too early?

Question:What triggered Person D to realise that he had entered track

too early?

The TOP administrative barrier failed

The general broadcast administrative barrier failed

Barrier Success:Emergency protocol was effective

Cultural threat: Normalization of deviance

Cultural threat: Production pressure

Cultural threat: Production pressure

Example electronic version of Learning Technique14

1a. Storyboard: (Events)

b. Storyboard: (Conditions)

2. Questions and Answers

3. Barrier Analysis

4a. Error Type

b. Reason for Error

5. Cultural Analysis

6. Insight and Improvement Record and document findings.

The Learning Tree Steps

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The Storyboard

Events: These nodes capture the events, actions or conditions related to the incident. The events should be organized chronologically so that Event #1 is on the left followed by subsequent events to the right. The events are used to create a storyboard of the incident.

A special characteristic of the storyboard is that there can be multiple perspectives regarding the series of events. For example, if Joe’s incident report suggests something different from Jane’s, both versions of the events are recorded (see next page for example).

Conditions: These nodes capture the significantenvironmental and contextual factors that may be present at the time of an event. Examples include weather, visibility, time of day, hours into the shift, or physical hazards. Conditions can be global, that is, can be present in multiple events.

Step 1

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The StoryboardJason arrives at the public works office at 5:45 am.

1At the morning briefing, Jason is assigned to work on front-end loader for the day.

2 3 4

Jason follows the pre-trip procedure and checks the fluid levels and tire pressure.

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Jason drives to the local transfer-site to pack-down the garbage bins.

6Jason gets out of the loader to grab loose garbage by hand b/c it is faster than by loader.

7Jason reported the handbrake malfunctioned and releases.

8a *

Eli suggests Jason did not engage the handbrake before leaving the loader.

8b**

The loader was on an slight forward gradient and the bucket was not on ground.

9The loader rolled forward and pinned his thighs between the bucket and a wall.

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Jason used his cell-phone to call a coworker to come out to the local transfer site.

11Coworker Eli arrived, but was inexperienced and had never operated a loader.

12Jason guided Eli how to use the joystick controls

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The loader rolled backwards. Jason experienced lacerated skin and bruising.

Jason did not report the incident out of fear of repercussion and embarrassment.

14 15Eli reported the incident a month later at a safety toolbox talk.

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Early morning shift.

Raining heavily all morning.

Working alone.

Step 1

Jason slips in the mud on his way over to the loader, his pants and jacket are soaked.

Jason attends the safety tool-box talk at 6:30 am. Then walks to the loader.

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The Q & A

Questions: questions help us capture our thought process that arises from the storyboard (or at any point in the process). For example, why did the employee not attach his safety harness, or was the correct procedure followed? These cards are designed to get the group to think about how or why the incident occurred. Questions do not necessarily need answers and questions may even lead to more questions.

Answers: These cards contain the answers to the question cards. If the group knows the answer to the question, they can use an answer card. The answer may not be complete but can be based on best available information. The degree of certainty can be noted. If the group is uncertain, it is possible to write a tentative answer and task someone to find an answer to the question.

Step 2

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The Q & A

Jason follows the pre-trip procedure and checks the fluid levels and tire pressure.

5

Jason drives to the local transfer-site to pack-down the garbage bins.

6Jason gets out of the loader to grab loose garbage by hand b/c it is faster than by loader.

7 8a *

8b**

The loader was on an slight forward gradient and the bucket was not on ground.

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The loader rolled forward and pinned his thighs between the bucket and a wall.

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Early morning shift.

Raining heavily all morning.

Working alone.

Why did Jason not put the loader bucket on the ground before exiting the loader??

He was collecting garbage inside the bucket, so it was curled upward and off the ground.

The bucket could have still been on the ground, even if it was curled upwards?

Maybe Jason was rushed or distracted when leaving the cab? Requires follow-up

Jason used his cell-phone to call a coworker to come out to the local transfer site.

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Why did Jason call a coworker to the site and not a supervisor?

He was friends with this coworkerand could trust that he would not tell the supervisor.

Why did he not notice a massive machine rolling towards him?

Jason was responding to a txt when struck. It was raining heavily.

Is texting against the policy?

Why what Jason working alone? It is common practice to work in teams.

Step 2

Policy is specific to inside vehicles but does not specify when outside vehicles.

Jason reported the handbrake malfunctioned and releases.

Eli suggests Jason did not engage the handbrake before leaving the loader.

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The Barrier Analysis

Barriers are the controls you have put in place to manage the hazards of the operation.

Barrier Failure: These nodes describe a barrier that failed during the event. There are different types of barriers, physical (e.g., safety harness snapped), system (e.g., inadequate safety policy) and behavioural (i.e., employee not following the rules or procedure).

Barrier Success: These nodes describe how barriers worked effectively. There are also three types (physical, system and behavioural). For example, a physical barrier stop someone from falling off a railing, a systematic policy removes cell-phones from the worksites, and employees behave in compliance with the rules. In addition, there is a fourth success barrier which is innovations (e.g., new and creative approach to solving problems), which is a successful response that is not specified by the system.

Step 3

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Jason believes the handbrake malfunctioned and released.

8a *

The investigator suggests Jason did not engage the handbrake before leaving the loader.

8b**

The loader rolled forward and pinned his thighs between the bucket and a wall.

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Why did he not notice a massive machine rolling towards him?

Jason was responding to a txt when struck. It was raining heavily.

The Barrier Analysis

A physical barrier failed, the mechanical handbrake broke.

Jason failed to engage the handbrake, his behaviour was the issue.

Jason follows the pre-trip procedure and checks the fluid levels and tire pressure.

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Jason followed the right pre-trip behaviour as written out in the pre-trip procedure.

Coworker Eli arrived, but was inexperienced and had never operated a loader.

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Eli failed to follow the procedure related operating equipment without training.

Step 3

Jason used his cell-phone to call a coworker to come out to the local transfer site.

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Jason did not follow the procedure of calling a supervisor when involved in an incident.

Is there a policy against texting?

Policy is specific to inside vehicles but does not specify when outside vehicles.

There is not a policy for cell-phone use when outside machinery.

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The Error Analysis

Error Type Cards: The barrier failures identified in step 3 are often directly connected to an error. There are three types of errors, the error is either due to skill, mistake, or violation. See Reason’s (1997) Managing the Risks of Organizational Accidents for more details. Skill-based errors involve an attention failure, that is, the employee knows the right procedure and intends to do the correct action, but for some reason, they fail to execute the correct action. For example, you intend to put sugar on your cereal, but you grab the salt because the containers look similar. Another example, you are a fighter pilot attempting a landing, and you pull the auto-eject lever instead of the landing gear lever because they are in a similar location. Mistake-based errors occur when the employee either misreads an environment or situation or does not have the right knowledge or expertise. For example, you smell an eggy odor in the air and blame your coworker for passing gas, when it is actually a natural gas leak. Another example, you are on an airplane when smoke fills the cabin. You rush into action and open the escape hatch over the wing, but this was a mistake, as you applied an incorrect rule (use nearest emergency exit) as you had mis-diagnosed the situation (did not realize there was an engine fire..Violation: This involves an active violation of appropriate behavior. For example, speeding in your vehicle, or deciding not to wear your fall protection because it is uncomfortable.

Reasons for Error Cards: Each error type often has an explanatory reason. Skill-based errors are often due to attentional failures (fatigue, distraction, or impairment). Mistake-based errors are often due to training or experience deficits. While violation errors are often due to production pressure, lack of supervision, or individual differences.

Step 4

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The investigator suggests Jason did not engage the handbrake before leaving the loader.

8b**

The Error Analysis

Jason failed to engage the handbrake, his behaviour was the issue.

Coworker Eli arrived, but was inexperienced and had never operated a loader.

Eli failed to follow the procedure related operating equipment without training.

Step 4

Jason intended to engage the handbrake, but failed to execute the action.

It was an early morning shift in heavy rain. Fatigue or weather distraction may be involved.

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Eli violated the operator’s procedure by moving the loader. If Eli did not move the

machine backwards, it could have cut off Jason’s legs. Time was of the essence.

Jason used his cell-phone to call a coworker to come out to the local transfer site.

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Jason did not follow the procedure of calling a supervisor when involved in an incident

Jason misread the seriousness of the situation or did not know the procedure when in an incident.

Perhaps it was inexperience or the shock of the situation that lead Jason to call Eli, instead of a supervisor. 23

The Culture Analysis

Culture: The investigation may provide insight into the culture of the organization. Culture is often described as the common behaviors, values, and beliefs of a collective group.

Cultural Threat: These are the cultural weaknesses that may be an indicator of your safety culture. Normalization of deviant behavior is a cultural threat whereby an unsafe behavior is conducted because everyone else is doing it. For example, many drivers regularly speed (deviant unsafe behavior) on the highway. Production pressure is an organizational attitude that prioritizes getting the job done quickly over getting the job done safely. For example, when you feel you should take a shortcut to get the job done on time. Complacency is the acceptance of below-par standards and practices. The phrases “good enough,” or “we do it because it is the way it has always been” are common.

Cultural Defenses: These are the cultural strengths that exist and can lead to a positive safety culture. A defense can be strong leadership, employee empowerment, or vigilance.

Step 5

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The Culture AnalysisStep 5

3

Jason attends the safety tool-box talk at 6:30 am. Then walks to the loader.

Jason did not report the incident out of fear of repercussion and embarrassment.

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Employee engagement in tool-box talks is a positive cultural defense.

A punitive blame culture may exist. Fear of reporting is leads to underreporting.

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The Improvement

Improvement and Insight Cards: The group reviews the information captured so far and looks for new insights they were unaware of before the exercise and potential improvement opportunities.

Insight cards: These nodes describe insights that have been gained from the event, these insights could be about how safety systems operate in practice or could be an insight into the safety culture. For example, the lack of a cell-phone use policy becomes apparent when it is a contributing factor in an incident.

Improvement Opportunity: These nodes describe ways the system could be improved, these do not need to be linked to the specific event, as they may arise for questions or insights. Improvements should include individuals accountable for leading the improvement action, as well as a timeline. For example, John, the foreman will be responsible for drafting a cell-phone use policy by September 30th. Implementation of the policy will start January 1st.

Step 6

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The ImprovementStep 6

Jason did not report the incident out of fear of repercussion and embarrassment.

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A punitive/blaming culture may exist. Fear of reporting leads to underreporting.

The loader rolled forward and pinned his thighs between the bucket and a wall.

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Why did he not notice a massive machine rolling towards him?

Jason was responding to a txt when struck. It was raining heavily.

Who was he texting? Does it matter?

There is not a policy for cell-phone use when outside machinery.

We did not think the existing cell-phone use policy needed to be specific to inside and outside vehicles.

John S will update the policy to reflect inside and outside cell-phone use by Sept. 30. Deployed Jan. 1

Leadership training to transform a punitive culture to a just and fair learning culture. 27

The Wrap-up

That is it, simple right? When your group can’t think of anything new, it means your learning tree has reached its saturation point. At this point, you will want to take photographs of the completed project (if you completed the physical version) or hit ‘save’ if you used the electronic version.

It will be important to capture the important information in a database (excel or access) so that you can begin to follow trends within your data. This allows for future tracking, learning, and accountability.

In some cases, when you have questions that do not have answers, you may need to find answers before you are finished. You can schedule a follow-up learning tree session to allow for the collection of follow-up information. If new insights or improvement actions are identified capture them in your photos and databases.

If you are interested in participating in a research project regarding your data, please contact HFLab@smu.ca. This will include free analysis and reporting of your Learning Tree data.

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