Multilinear%20Events%20Sequencing

1
Multilinear Events Sequencing

• MES incorporates timelines into sequential
  diagrams, providing a scale that parallels the
  sequences of events to show the time
  relationships between events and the incident.
• The method distinguishes between actors, actions
  and events.

2
Definitions

• An event is one actor performing one action
• Primary Events are directly tied to the accident
  sequence
• Secondary Events are events that play a role in
  the accident but are not directly part of the
  accident sequence
• Secondary Events are tied to the Accident
  Sequence of Events with vertical lines
• Conditions differ from events insofar as they
• (a) describe states or circumstances rather than
  happenings or occurrences and
• (b) are passive rather than active

3
Cause Mapping

• Cause Mapping utilizes the fundamental principles
  of systems thinking to identify the basic cause
  and effect relationships of any problem.
• Cause Mapping is a 3-step problem solving process
  for defining, analyzing and solving any type of
  problem.
• The steps in Cause Mapping are
• Step 1 Problem Outline the problem by asking
  who, what, when, and where?
• Step 2 Analyze Develop the Cause Map beginning
  with the unwanted outcome. Working to the right,
  identify the preceding cause(s)
• Step 3 Solutions Identify the best possible
  solutions.

4
Multilinear Events Sequencing (MES)

• Designed to detect hazards arising from the time
  relationship of various organizational
  activities.

5
MES-diagrams

• A MES-diagram portrays the accident being
  investigated as a sequence of causally connected
  events, which represent activities.

6
Event Blocks

• Each event block contains the following
  information about its event description of the
  action
• Actor the object or person that performed the
  action
• Time of event

7
Causation

• Event blocks are connected via arrows that
  represent causation.
• If event X was necessary for event Y to occur,
  then MES-diagram contains an arrow from X to Y

8
MES Diagrams

• MES-diagrams have two axes
• The horizontal axis represent time
• The vertical axis lists actors involved in the
  accident
• Event blocks are placed on the diagram according
  to their time and actor
• Any relevant information that does not fit event
  block structure can be placed on MES-diagram as a
  condition
• A condition is an oval with some text inside
• A condition is linked to an event block via an
  arrow

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MES Diagram
10
MES-diagram Process

• Events are identified
• Causal connections between events are identified

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Counterfactual reasoning

• Counterfactual reasoning is a way to establish
  causal dependency between events
• We may define a cause to be an object followed by
  another, and where all the objects, similar to
  the rest, are followed by objects similar to the
  second.
• Or, in other words, where, if the first object
  had not been, the second never had existed.

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Acid Test of MES

• To determine if the MES charting is correct, the
  investigator must determine
• Given the actors, events, actions, and
  sequencing, will the scenario developed result in
  the same outcome?
• If the answer is yes, then the MES is complete
• If the answer is no, then there are gaps in the
  MES

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Using MES for Accident Investigations

• Examine each arrow (causal links between events)
• Develop countermeasures at each causal link

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Activity 5

• Perform a literature search and identify one
  accident scenario or use a work accident you are
  familiar with.
• Remove all descriptors (ie company name,
  employee names, etc)
• Using the scenario, apply the Multilinear Events
  Sequencing technique to develop a causal map of
  the accident.
• Complete the assignment and upload the activity
  to your instructor through D2L by the due date in
  the course syllabus.