by ThinkReliability Staff

The occurrence of dog attacks is a significant ongoing problem.  An estimated 4.5 million people are attacked each year, of whom 800,000 seek medical care.  These statistics only include attacks that were significant enough to be reported, so the actual incidence is no doubt larger.  One action that has been taken to reduce the incidence of dog attacks is banning specific dog breeds associated with aggressive tendencies (mostly large breed dogs like Pit Bull Terriers, Boxer Dogs, and German Shepherd Dogs), known as Breed Specific Legislation (BSL).

Although BSL is gaining popularity, it does not address all the causes of dog attacks.  A root cause analysis of dog attacks identifies factors related to the dog (inherent temperament, socialization, protective tendencies, location and level of restraint), the owner (treatment and control of the dog) and the victim (behavior, location, age and experience with dogs).  The etiology of a dog attack is multifactorial and as such, should be dealt with in a broad and diverse approach.

Some suggested alternatives to BSL that take into account the complex nature of dog attacks and are targeted at preventing all dog attacks follow:

– Education about proper behavior around dogs would greatly decrease the potential for dog attacks.  Approximately 80% of attacks are by a known dog and more than half of attacks are against children under 12, suggesting that human behavior around a dog is an important trigger since children are more likely to engage in activities that may be perceived as threatening (such as loud noises, running, improper touching).

– Proper enforcement of existing legislation is a readily available method of reducing dog attacks, as many municipalities have restraint laws that are poorly enforced.  An attack cannot occur without the interaction of a dog and person.  Proper restraint on and off private property would reduce the potential for attacks.

– Stricter regulations and more frequent inspections of breeding operations could play a role in reducing improper treatment of young dogs.  Early socialization plays a large role in that puppies that have little interaction or negative interaction with humans are more likely to develop aggressive tendencies.  In most cases this early interaction occurs within breeding operations.

– Encouragement of voluntary spaying and neutering takes advantage of a widely available procedure to reduce the potential for dog attacks.  One of the most significant predictors of attack is a sexually intact dog.  Outside of a breeding operation there is little reason for not spaying or neutering, and the procedure can have additional benefits for the health of the animal, help control the dog population, and reduce unwanted dogs.

To view the PDF file including the root cause analysis of a dog attack, please click “Download PDF” above.

By ThinkReliability Staff

On July 25, 1956, the Andrea Doria (an Italian luxury passenger liner) was struck off Nantucket by the Stockholm (a Swedish passenger liner).  Andrea Doria was struck head on, which was bad enough.  What made it even worse was that Stockholm was outfitted with a reinforced icebreaking bow for its travels in frigid waters.  If you look at the severe damage to Stockholm’s reinforced bow (estimated to be $1 M in 1956 dollars), it’s no surprise that Andrea Doria suffered fatal damage.

Although one lesson we can take from this is to never be arrogant enough to call your ship “unsinkable”, we can perform a root cause analysis into the tragedy to determine what else went wrong.  A thorough root cause analysis built as a Cause Map can capture all of the causes in a simple, intuitive format that fits on one page.

First, we look at the impact to the goals.  51 people were killed (46 on Andrea Doria, 5 on Stockholm).  This is an impact to the safety goal.  The $29 million (in 1956 dollars) Andrea Doria was a total loss, and  Stockholm suffered $1 million worth of damage.  These are both impacts to the material goal.

When Stockholm struck Andrea Doria, it ripped a 50×30 foot hole in Andrea Doria.  This compromised Andrea Doria’s watertight compartment system (one of the features that made it “unsinkable”), so it began to take on water.  Within 5 minutes of the collision, it was listing 20 degrees starboard.  It was designed to stay afloat with a 15 degree list (another “unsinkable” feature), but not as much as 20, so the ship sank.

Now, why did the Stockholm’s bow strike Andrea Doria’s side?  Stockholm turned starboard, trying to avoid Andrea Doria because they were on a collision course.  The turn was insufficient because of a delay in response time by Stockholm while they plotted the course of the oncoming vessel, which was standard procedure, and because their speed was not reduced.  Both the delay and the speed not being reduced were partially caused by an inexperienced watch – a 3rd mate was in charge and he was the only officer on deck.  It is also believed that the navigator on Stockholm was unaware of the fog.  (Note that although Andrea Doria was in extremely thick fog, Stockholm sailed in clear skies until just before the collision.)  Andrea Doria’s starboard side was exposed because they made a hard left turn, attempting to avoid Stockholm, which was also insufficient due to their speed, which was not reduced sufficiently because the ship was trying to make good time.  Operations in fog call for “moderate speed”, which is defined as the speed at which a ship could be stopped within its visibility distance.  Andrea Doria’s visibility was 1/2 mile, while its stopping distance was far greater.  (While Stockholm had not yet reached the fog, Andrea Doria was already in it, which would seem to be reason enough to reduce speed.)  We’ll also tie the fact that they were on a collision course as a reason for the impact.

How did the two ships get on a collision course?  Andrea Doria made an unexpected turn, to attempt to pass Stockholm starboard to starboard, despite the fact that ships normally pass port to port, per rules of the road.  They did this because they believed Stockholm was already to their starboard side.  They were unaware of Stockholm’s course because they did not plot it (possibly because the Captain was relying on his two state of the art radar systems).  Additionally, Stockholm was north of its recommended route, because the recommended route added distance and time, and was very crowded.

Stockholm turned starboard, to try and avoid Andrea Doria; however, Stockholm had miscalculated Andrea Doria’s position and course, partially due to ineffective navigation on Stockholm.  (Either Stockholm’s radar was providing incorrect data  or, as some experts believe, the radar data was being misinterpreted because the scale, which had to be manually set, was on the wrong setting.)

The ships also suffered from a lack of communication:  Stockholm was not using proper signals (its fog horn and turn signal).  There was no visual contact between the ships due to reduced visibility from fog and the fact that the ships were traveling at night.  Also, there were no radios to communicate between the ships (a fact that has thankfully been remedied).  The attached PDF, available for download, has a high-level visual root cause analysis (cause map) of the incident.  Even more detail can be added to this Cause Map as the analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.  (In the case of Andrea Doria, the high level cause map has 16 boxes; the detailed map has more than 100.)

By ThinkReliability Staff

On August 14, 2003, over 50 million people in the U.S. and Canada were without power, some for several days.  Damages from the loss of power – including damaged refrigerated items and looting – totalled approximately $6 billion (U.S.).  508 generating units shut down, resulting in the loss of border and port control systems.  After the blackout, a U.S.-Canada Power System Outage Task Force was appointed to investigate the cause.  We will use the data they obtained to perform a root cause analysis of the event.  A thorough root cause analysis built as a Cause Map can capture all of the causes in a simple, intuitive format that fits on one page.

The blackout was triggered by a shut-down cascade, unsustainable power surges in numerous transmission lines.  This occurred due to a supply/demand mismatch – a large decrease in available power without load shedding (where operators drop some consumers off the grid to prevent outages).  Operators did not shed loads because they weren’t warned of impending outages, due to a lack of communication from FirstEnergy, the company whose lines began shutting down first, and a lack of warning by the regional coordinator.

The decrease in available power was due to a key transmission line being shut down.  This happened because the line contacted overgrown trees when it sagged due to a power surge because other, smaller lines shut down when they sagged and touched overgrown trees.  The lines originally sagged due to power surges caused by an automatic shutdown of a power generating unit.  The power surge could have been stopped by operators shedding loads, but they did not because they were not immediately aware of problems, thanks to a failure in their grid monitoring equipment, and due to a lack of training.

Due to the complexity of the event, it is possible to make a much more detailed Cause Map.  As with any investigation the level of detail in the root cause analysis is based on the impact of the incident on the organization’s overall goals.  For example, this map has 21 boxes.  The detailed map that includes the findings of the Task Force has more than 70 boxes, and is at a more appropriate detail to find solutions to ensure that this sort of energy reliability problem does not happen again.

By ThinkReliability Staff

Currently, more than 43 million Americans smoke.  Why does this happen, and what effect does it have?  We will do a very simplistic root cause analysis.  A thorough root cause analysis built as a Cause Map can capture all of the causes in a simple, intuitive format that fits on one page.

Smoking leads to an estimated 440,000 premature deaths each year.  This includes deaths caused by smoking and by exposure to secondhand smoke.  Additionally, 8.6 million people suffer from smoking-related illnesses.  And, 900 infant deaths are caused annually from smoking during prengnancy.  These are all impacts to the safety goal.  The deaths and diseases are caused because smoking raises the risk of cancer, cardiovascular disease, and respiratory disease.  The first two are caused by exposure to tobacco smoke (including secondhand smoke) and the third is caused by inhalation of smoke.  Either way, the cause is that many people smoke cigarettes.

Why do people smoke?  Well, it’s because they start smoking and because it is extremely difficult to quit.  There are many reasons why it is difficult to quit.  Some of these reasons are: cigarettes are extremely addictive, severe withdrawal symptoms cause relapses, smokers have a lack of assistance in quitting, they are afraid of weight gain, and there is a lack of increase in the cost of cigarettes.  This last one sounds odd, but studies have shown that an increase in the cost of cigarettes decreases the number of smokers.  However, the cost of cigarettes does not reflect the true cost of cigarettes (based on health costs and productivity losses), and the small increase in taxes (which has not kept up with inflation) is offset by cigarette company promotions.

People start smoking because of the positive imagery of smoking – the heavy advertising and promotion of cigarettes, smoking in popular culture (mainly movies), and the lack of counter-advertising by federal organizations and anti-smoking campaigns.  Additionally, most smokers (90%) start as children (before the age of 18) because cigarettes entice children, there is a lack of counseling against their use, teens may suffer from peer pressure encouraging, and teens are more susceptible to addiction than adults.

By ThinkReliability Staff

Unfortunately, an investigation into a deadly construction accident is currently underway in New York City.  On Saturday March 15, a 19 story crane collapsed.  Four construction workers were killed and 18 others were injured.  Emergency workers are still sorting through the rubble in an attempt to find any remaining survivors.   The crane was being used at a high-rise construction site and was attached to the side of a skyscraper.  Details as to why the crane fell are still vague, but eye witnesses report that a piece of steel fell and severed at least one tie that held the crane onto the building. Once the connection between the crane and the building was weakened, the crane toppled and split into two pieces.  As it fell, the crane smashed a 4 story townhouse and damaged parts of 3 other buildings.

What made the crane fall?  Part of doing a root cause analysis is sorting the pertinent facts from all the information that is available.  Is it relevant that neighbors had complained that the construction crews were working illegal hours and it seemed like the building was going up too quickly?  City officials had issued 13 violations to the construction project, which at first glance seems like a red flag indicating a lack of attention to safety.  But Mayor Bloomberg has said that this is a normal number of violations for a project this size.  Additionally, the crane had been inspected on the day before the accident and no violations were issued.  Did something change in 24 hours or was the inspection inadequate?  At the time the crane fell, it was being raised to enable work to begin on the next floor of the building.  Did this contribute to the accident?  Where did the piece of steel come from that supposedly fell?  At this point in the investigation there are more questions than answers.

There are many facts and theories that surface in the wake of any accident, and part of doing a root cause analysis is determining which are actually relevant.  This is a process that is much easier said than done.  The push to provide answers quickly can add to the pressure to produce a “cause” for the accident.  But as anyone familiar with the concept of root cause analysis knows, there isn’t a single “cause”, there are many causes that contributed to the accident.  The best approach is to record all possible causes and continue to gather evidence until you can eliminate all the noise and are left with the true causes.  Then the work of creating solutions that address the causes can begin.