New Zealand OHSIG Conference     26-28 October 2011 Hypothesis Forming and Testing               Roger Kahler        Engin...
Two Applications1. “Collective” Incident Data2. An “Individual” Incident Engineering Safer Workplace Solutions
Scientific Process     Interacting Concepts     • Models / Modelling• Hypothesis forming and testing         • Taxonomy Ca...
TaxonomyEngineering Safer Workplace Solutions
Crane Fatalities – A Taxonomic Analysis                                                      Overhead power               ...
Taxonomies• Show relative frequency of levels of Damage• Show relative importance of different damaging  energies         ...
Incident Time Base• Damage as a consequence of an Energy Exchange       Situation stable       Situation moving out of c...
Damage ReductionEngineering Safer Workplace Solutions
Damage ReductionEngineering Safer Workplace Solutions
Hypothesis Forming & TestingHypothesis Forming & Testing       as applied to    Individual Incidents     Engineering Safer...
What’s Your Hypothesis? Engineering Safer Workplace Solutions
What Actually HappenedVideo available athttp://www.youtube.com/watch?v=LVmpEPdPBk8        Engineering Safer Workplace Solu...
An Individual Incident• What are the roles of  – Taxonomy  – Modelling  – Hypothesis Forming and Testing       Engineering...
Role of Hypothesising in the              Journey of an Investigation•   Scope•   Collect Information Data ← Informally•  ...
Observers• Incident Investigators are first and  foremost observers of a situation• Observations have to first be made• A ...
ObservationAn observation will be:1.   SUPPORTIVE of the hypothesis2.   REJECTING of the hypothesis3.   NOT APPLICABLE to ...
Hypothesis• At some point a decision has to be made  with respect to the observations• This involves forming a hypothesis ...
Possibility and Probability    IMPOSSIBLE           -         POSSIBLE                                       PROBABILITY50...
Self Fulfilling Hypothesis• Hypothesise• Select evidence to support, not reject                Engineering Safer Workplace...
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing                                                   Car „A‟                 Start of         ...
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and Testing    Engineering Safer Workplace Solutions
Hypothesis Forming and TestingHow could you formally test an hypothesis?         Engineering Safer Workplace Solutions
Hypothesis Forming and Testing        Hypothesis = (testable statement)“Supporting”           “Rejecting”                 ...
Engaging Experts   Questions to People Investigating Failures1. What do you think happened? (Hypothesis)2. Why do you thin...
Case Study – Low Loader Fire• List supporting and rejecting observations for each  hypothesis• Decide whether the particul...
The EndEngineering Safer Workplace Solutions
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Hypothesis Forming and Testing

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Roger Kahler
Director, InterSafe Group Pty Ltd

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Hypothesis Forming and Testing

  1. 1. New Zealand OHSIG Conference 26-28 October 2011 Hypothesis Forming and Testing Roger Kahler Engineering Safer Workplace Solutions
  2. 2. Two Applications1. “Collective” Incident Data2. An “Individual” Incident Engineering Safer Workplace Solutions
  3. 3. Scientific Process Interacting Concepts • Models / Modelling• Hypothesis forming and testing • Taxonomy Can be applied collectively/individually Engineering Safer Workplace Solutions
  4. 4. TaxonomyEngineering Safer Workplace Solutions
  5. 5. Crane Fatalities – A Taxonomic Analysis Overhead power Electrical Energy – lines - 214 electrocution - 217 Portable equipment -3 Falls of Objects -Crane Fatalities Gravitational 1441985-1995 Energy - 268 Falls of People - 88525 Falls of Crane – overturn - 36 Machine Energy - Person Caught 34 Between - 24 Person Run Over - 10 Other - 6 Engineering Safer Workplace Solutions
  6. 6. Taxonomies• Show relative frequency of levels of Damage• Show relative importance of different damaging energies Engineering Safer Workplace Solutions
  7. 7. Incident Time Base• Damage as a consequence of an Energy Exchange  Situation stable  Situation moving out of control  Situation out of control Time  DAMAGE  Recovery Engineering Safer Workplace Solutions
  8. 8. Damage ReductionEngineering Safer Workplace Solutions
  9. 9. Damage ReductionEngineering Safer Workplace Solutions
  10. 10. Hypothesis Forming & TestingHypothesis Forming & Testing as applied to Individual Incidents Engineering Safer Workplace Solutions
  11. 11. What’s Your Hypothesis? Engineering Safer Workplace Solutions
  12. 12. What Actually HappenedVideo available athttp://www.youtube.com/watch?v=LVmpEPdPBk8 Engineering Safer Workplace Solutions
  13. 13. An Individual Incident• What are the roles of – Taxonomy – Modelling – Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  14. 14. Role of Hypothesising in the Journey of an Investigation• Scope• Collect Information Data ← Informally• Form and test hypotheses ← Formally• Description• Analysis and Recommendation Engineering Safer Workplace Solutions
  15. 15. Observers• Incident Investigators are first and foremost observers of a situation• Observations have to first be made• A frame of reference will improve the quality and quantity of observations Engineering Safer Workplace Solutions
  16. 16. ObservationAn observation will be:1. SUPPORTIVE of the hypothesis2. REJECTING of the hypothesis3. NOT APPLICABLE to the hypothesis4. MORE INFORMATION REQUIRED before a decision can be made as to 1, 2 or 3. Engineering Safer Workplace Solutions
  17. 17. Hypothesis• At some point a decision has to be made with respect to the observations• This involves forming a hypothesis Engineering Safer Workplace Solutions
  18. 18. Possibility and Probability IMPOSSIBLE - POSSIBLE PROBABILITY50% 95% 99%Balance of 1:20 “Variation due Beyond reasonableprobabilities to chance” doubt Engineering Safer Workplace Solutions
  19. 19. Self Fulfilling Hypothesis• Hypothesise• Select evidence to support, not reject Engineering Safer Workplace Solutions
  20. 20. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  21. 21. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  22. 22. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  23. 23. Hypothesis Forming and Testing Car „A‟ Start of curve Double white lines 100 m 2 skid marks 20 m long gridHYPOTHESIS: Car „A‟ braked heavily after crossing grid.Questions: What observations can you make that could be “supportive” or“rejecting” of this hypothesis? Engineering Safer Workplace Solutions
  24. 24. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  25. 25. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  26. 26. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  27. 27. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  28. 28. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  29. 29. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  30. 30. Hypothesis Forming and Testing Engineering Safer Workplace Solutions
  31. 31. Hypothesis Forming and TestingHow could you formally test an hypothesis? Engineering Safer Workplace Solutions
  32. 32. Hypothesis Forming and Testing Hypothesis = (testable statement)“Supporting” “Rejecting” CommentsObservations Observations Engineering Safer Workplace Solutions
  33. 33. Engaging Experts Questions to People Investigating Failures1. What do you think happened? (Hypothesis)2. Why do you think this? (Supporting information)3. Any observations that don’t fit? (Rejecting information)4. What could be done differently in future? (Essential factors & potential recommendations) Engineering Safer Workplace Solutions
  34. 34. Case Study – Low Loader Fire• List supporting and rejecting observations for each hypothesis• Decide whether the particular hypothesis is possible/impossible• Of the possible hypothesis, assign a probability Engineering Safer Workplace Solutions
  35. 35. The EndEngineering Safer Workplace Solutions

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