Engineering as Social Experimentation

Transcription

1 Engineering as Social Experimentation Engineering/Experimentation Comparison Engineering Objective is to solve problems which often involves: - unknowns - uncertain outcome - monitor, learn from past experiments - human subjects / participants often unaware, uninformed - often don't recognize all variables - natural experiment Experimentation Objective to find new knowledge or answers which also involves: - unknowns - uncertain outcome, test hypothesis - draw conclusions or verify hypothesis based on experience / evidence - "informed consent" of subjects - try to control all variables - controlled experiment Responsible Experimenters: Conscientious open eyes, ears, mind - protect the safety of human subjects, providing a safe exit whenever possible, and respect their right of informed, valid consent* (knowledge & Voluntariness) - use imaginative forecasting of possible side effects, and reasonable efforts to monitor them - have autonomous, personal involvement in all aspects of a project - accept accountability* for the results - display technical competence and other attributes of responsible professionals (Martin & Schinzinger, Introduction to Engineering Ethics, 2 nd Ed., 77-94) Informed Consent Knowledge All information needed to make a reasonable decision Voluntariness No force, fraud or deception Valid Consent Given voluntarily Based on info in understandable form Competent consenter Where subjects are not individually identifiable Info widely disseminated Consent by proxy Milgrams Experiment Unwitting subject ordered to shock subject (actor) People generally defer to authority Don t feel responsible Have a tendency to conform Safety and Risk (26/40 administered the highest, 450V, shock; none refused before 300V!) 1

2 What does safety mean? It is an engineers duty (paramount) to protect the safety and well being of the public (re: code of ethics) Safety is the freedom from damage, injury or risk Risk is the possibility of suffering harm or loss (American Heritage Dictionary) A risk is the potential that something unwanted and harmful may occur In examining safety, we must acknowledge that the public can be active consumers (informed, voluntary); that is they actively participate in the use of a product (their choice) even though they know there are risks Hang gliders, bungee jumping etc. But the public can also be passive consumers (uninformed, involuntary) in that they need/choose to use a product, but are not directly involved in the decisions that affect their personal risk. (e.g. electrical power, water, airline passengers etc.), Safe (Lowrance, modified) Companies, Inc. The Public can also be bystanders ; not directly involved in its use, but affected by it (e.g. second hand smoke!) A thing is considered safe if, were its risks fully known, those risks would be judged acceptable, in light of settled valued principles*. * rational, enduring, long term principles; not affected by transient emotion or temporary conditions 2

3 Factors associated with risk (page 64, Fledderrmann) Voluntary vs. involuntary risk We will take higher risks if voluntary E.g. Going to a bar where smoking is involved and being aware of the effects of second hand smoke Short term vs. long term consequences We accept higher risks if the effect occurs in the distant future E.g. cancer from smoking versus injuries from a motorcycle accident We accept higher risks if reversible (e.g. broken leg vs losing an arm) Proximity: more sensitive to losses if closer to home Factor associated with risk (cont.) Expected probability We will discount the risk if the probability is extremely low E.g. avoid jellyfish sting, but accept shark attack Threshold level of risk We will accept low levels of exposure We ignore nuisance risks E.g. if probability or consequences re low enough, we won t be bothered (crossing the street ) Effect of Information: Companies, Inc. P134 How information is presented can affect how it is interpreted. For example: Consider the outbreak of an unusual disease expected to kill 600 people. Two alternative programs are proposed. Assume the exact scientific extimates of the outcomes are as follows: One group asked to select either: Program A 200 people will be saved Program B P=1/3 that 600 will be saved P=2/3 that nobody will be saved Result: 72% chose A, 28% chose B. Companies, Inc. Second group asked to select either: Program C 400 people will die Program D P=1/3 that nobody will die P=2/3 that 600 will die Results: 22% chose C (same as A), 78% chose D (same as C) Bottom line Decisions are always based on our perception of the risk vs the benefit, or the potential loss vs the potential gain. may be distorted by: biases, inaccurate information, emotion AND presentation. For engineers have to figure out what we need to consider to fulfill our role May evolve as society changes 3

4 Back to Safety vs. Risk Martin, Mike W. and Roland Schinzinger, "Ethics in Engineering", Third Edition, McGraw-Hill Companies, Inc. 1996, p141. Total Production costs of products is dependent on both product cost and safety costs. As the risk increases, the cost to produce decreases, but the safety costs increase (litigation, insurance etc) Product Lifecycle Cost Primary Costs Secondary Costs Least Risk Most Pinto Case Assumptions (Harris, Pritchard, Rabins) Liabilities: 180 burn deaths, 180 injuries, 2100 vehicles $200K/death, $67K/injury, $700/vehicle Total: $49.15M Costs: $11/car, $11/truck, 11M cars, 1.5M trucks Total: $137M Benefits and risks on both sides here Risk-Benefit Analysis Usually applied to large projects Risk and Benefits are assigned a dollar value Problems (and questions): Comparing apples and oranges Time shifting of risks/benefits Who benefits and who takes the risks? Some terms: Probable gain Prob. Success X Value E.g. 50% chance of success; $1M project = $.5M Probable Loss Prob. Failure X Value Uncertainties in Design Absolute safety neither practically attainable nor affordable. Expected performance vs expected duty Safety margin gap between capability and duty Safety factor Ratio of average capability/duty 4

5 Uncertainties in Design Expected performance vs expected duty Safety Factor=B/A Safe Designs Design must comply with all applicable laws (readily available) Duty Safety Margin Capability Designs must meet acceptable engineering practice (this term can be vague but continuous upgrading of skills through short courses and extensive literature searches can help here) A B Stress Safe Designs (cont.) Safety consideration must be included in design from the start Alternate designs that are potentially safer must be considered Compare what you have to other approaches that are deemed safe Foresee potential misuses of the product and design to avoid them Courts are sympathetic to the stupid user Warning labels ARE NOT sufficient Safe Designs (cont.) Products must be extensively tested Failure analysis techniques Checklists Hazard and Operability (HAZOP) Failue modes, effects critical analysis (FMECA) Fault tree of Event tree analysis Some misconceptions about risk and safety Assumption: Operator error and negligence are the principle causes of all accidents. Reality: Accidents are caused by dangerous conditions that can be corrected by design. E.g. automatic couplers for rail cars gretly reduced accidents. Assumption: Making a product safe invariably increases costs Reality: Initial costs need not be higher if safety is built into a product from the beginning; life cycle costs are lower. Design corrections later are very costly. Companies, Inc. 5

6 Assumption: We learn about risks after a product has been introduced Reality: Using imagination, forecasting, lookinf at similar products and experiences, simulation etc. can prevent many risks (and costs) before introduction. Assumptions: Warnings about hazards are adequate; insurance coverage is cheaper than planning for safety Reality: Depending on how well the warnings are displayed, this could cost big bucks in litigation. Warnings indicate that a hazard may exist. They do not provide protection!! Liability You are liable for everything you do and design; simple fact! You cannot rely on codes and standards alone. This is called minimal compliance and does not guarantee a safe product nor does it provide a valid excuse if a product fails or someone is hurt. Engineers are often compromised by timelines of their employer and do not spend the time necessary to look at safety in depth. You are not protected from liability just because you are part of a large company!!! Lessons from 3-Mile Island Wisdom and fallacy in public perceptions Safety should be integral part of design, anticipate possible failures Share information when it comes to safety People are overly optimistic about things that haven t hurt them yet Lessons for Engineers: Perceptions change slowly (like OURS!) Watch for filters ; don t be blind to new info Expert opinion has limited value Don t be so sure Look hard for the wisdom. Don t discount public opinion too quickly! Companies, Inc. 6