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Have you ever been so sure your calculations were correct that you’d spend a good deal of money to implement a project? Or, did you bank on certain research only to find that you completely overlooked a crucial factor, but by then it was too late and the cost to fix the problem was sky-high? The central problem is determining uncertainty, which is the focus of risk analysis. Even the best, most thorough analysis can miss something, however--especially when assumption plays a role.
That’s what happened on Macquarie Island, a World Heritage site and the planet’s only island formed entirely of oceanic crust. Located between Tasmania and Antarctica in the Southern Ocean, Macquarie Island is home to 3.5 million sea birds and 80,000 elephant seals that go there to breed each year.
Cats were introduced on Macquarie Island in 1828 and rabbits 60 years later, both by sealing gangs and passing ships. The rabbits began to gobble up huge swaths of vegetation and quickly overpopulated, devastating the landscape and endangering the island’s burrow-nesting birds. This led authorities to introduce a European rabbit flea that carried the Myxoma virus. The virus worked and the rabbit population dropped from 130,000 in 1978 to about 20,000 within several years, allowing the vegetation to grow back.
But that made the cats unhappy. Because there were fewer rabbits to prey on, the cats began to feast on the native seabirds. By the mid-1980s, this was having a significantly negative effect on the seabird populations.
Authorities decided it was time to take action. The idea was that by removing the cats, the bird population would be saved. The scientists calculated that the rabbit population would only grow slightly, due to the Myxoma virus controls. The cat-eradication campaign started in 1985 and ended in 2000. But the rabbits meanwhile waged a population war, unexpectedly exploding onto the scene in greater numbers than before.
This underestimation compromised decades of conservation efforts at a cost of $24 million (Australian) to the Australian and Tasmanian governments, along with widespread ecosystem devastation.
“Rabbit numbers on Macquarie Island have returned to precontrol levels, and this can be clearly ascribed to the removal of cats,” says Dana Bergstom, Ph.D., of the Australian Antarctic Division and lead author of “Indirect Effects of Invasive Species Removal Devastate World Heritage Island” (British Ecological Society, Journal of Applied Ecology, January 2009). “The eradication of cats was positioned in a commendable, integrated pest-management framework, but the unintended consequences have been dire.”
According to Bergstrom, “Satellite images show substantial island-wide rabbit-induced vegetation change. By 2007, impacts on some protected valleys and slopes had become acute. We estimate that nearly 40 percent of the whole island area had changed, with almost 20 percent having moderate to severe change.”
Suddenly it was clear to everyone that the rabbits would have to be eradicated, too, or the island would be doomed. Already there were petrel deaths from rabbit burrowing, and other bird deaths from lack of vegetation for nesting. Whole swaths of land formerly covered with tall indigenous grasses and shrubs were barren, leaving no place for nesting birds. Rabbit warrens littered the landscape. Rats and mice were picking up where the rabbits left off, eating the birds’ eggs and killing off their young. It was the beginning of an avian specicide.
“A long-held assumption was that continued use of the Myxoma virus as a control measure would keep rabbit abundance low,” says Bergstrom.
However, it was the combination of the cats and the virus that caused the rabbit population to remain in check all those years.
“With the luxury of the wisdom of hindsight, we can suggest that the current situation arose as a consequence of inadequate recognition of top-down control of rabbits by a population of only 160 adult cats,” says Bergstrom.
Even though scientists conducted exhaustive research into the problem, and deemed the risk of eradicating the cats worthwhile to preserve the bird population, by underestimating the effect of the cats, and overestimating the effect of the virus on controlling the rabbits, the research hurt more than it helped. In fact, the devastation caused by the rabbits led to new and more costly ecological problems.
“The lessons for conservation agencies globally is that interventions should be comprehensive, and include risk assessments to explicitly consider and plan for indirect effects, or face substantial subsequent costs,” concludes Bergstrom.
A universal lesson, applicable everywhere, is that even when all the data are compiled, there is still always the chance that something will be overlooked.
Never assume anything.
In last month’s “Do the Math” we sent you to a blog for Assembly magazine with an error so bad it could have put an eye out. OK, not that bad, but I needed a good segue. The blog contained the following statement:
“In 2004, there were 36,680 job-related eye injuries in the United States, according to the federal Bureau of Labor Statistics (BLS). That’s more than 1,000 per day!”
As one reader was quick to point out “I calculate it to be just over 100 per day. Good thing I have good vision.”
Of course, even 100 per day are too many eye injuries. So thanks to Assembly magazine for giving us this statistic (even if there was a bit of goof in it).
The winner of this month’s “Do the Math” is Pete Nico. Nico wins a great prize from woot.com, which we will eventually deliver. Great prizes take time.
Next month’s puzzle
This month we’re going to throw a tough one at you. This isn’t strictly a math error but a common error made when looking at and describing statistics. It is so common that many might not recognize it as an error.
To see this, go to www.asq.org/quality-progress/2008/12/salary-survey/salary-survey-2008-seeing-green.html. You may have to register to see this article. (It’s free and, anyway, Quality Progress often has good information so it can’t hurt to sign up.) There is no need to look at the charts. The problem lies within the text. Thanks to Steve Osborn for this submission.
Send your answer to http://www.qualitydigest.com/contact?category=Comments. A randomly selected respondent will get a fantastic(ally cheap) prize from woot.com.
Remember, send us your math error. If we use it, you get a prize.
The Zero Defects Option-- Book Review Weak leadership means poor quality, according to author Dave Crosby in his book The Zero Defects Option (The Crosby Co., 2008). The Zero Defects concept states that all errors can be traced to just three causes… all in the control of the leader. If the leader understands the cause of defects, action can be taken to prevent their recurrence.
“Quality is easy,” says Crosby. “Dealing with angry customers, and explaining scrap, rework, and warranty payouts is a lousy job. It’s a rotten way to spend your day. Preventing defects means money, peace, and quiet.”
According to Crosby, the Zero Defects premise is that, “Every leader has the option to have work done right, or not. If you’re the leader, preventing defects is your option.”
Zero Defects is an idea that was discovered in the early 1960s and enjoyed success for about a decade, says Crosby. After that, quality-type programs--such as total quality management (TQM), SPC, and ISO 9001--sucked up all the oxygen, effectively putting Zero Defects in the hinterland of quality management. Regarding Six Sigma, Crosby views it as a “gimmick.”
“The biggest problem I have with Six Sigma is the use of Six Sigma as a performance standard--three mistakes in a million. Sigma signifies standard distribution, the distribution around a variable average. Six Sigma is being applied to attributes. How do you average an attribute?” asks Crosby.
The Zero Defects Option is relatively short, at 100 pages, and offers Seven Principles of Defect Prevention that a leader must observe to eliminate mistakes.
For further information, visit www.qualitynews.com.
According to the National Science Foundation, manufacturers are facing a troubling shortage of new blood in the field of engineering. A recent survey by Harris Interactive conducted on behalf of the American Society for Quality (ASQ) between November and December 2008, asked parents and youth, ages 8 to 17, their perceptions about a career in engineering. Results indicate that 85 percent of youth were not interested in a career in engineering. Why?
“The shortage of 70,000 engineers by 2010 will likely cause less focus on innovation toward quality,” says Cheryl Birdsong-Dyer, ASQ member and process engineer. “In addition, knowledge transfer from retiring engineers to incoming engineers will continue to weaken, threatening progress. This will increase infrastructure costs for generations to come.”
Parents often play a role in career considerations, but although the vast majority of parents (97%) believe that knowledge of math and science will help their children have a successful career, only 20 percent of parents have encouraged their children to consider engineering.
For kids, the reasons behind this lack of interest range from little knowledge about the field (44%), to not feeling confident enough in math or science to be competent in engineering (21%), to the desire for a more exciting career (30%).
Parents also accounted for the gender differences in the consideration of a career in engineering--31 percent of boys vs. 10 percent of girls say that their parents have encouraged them to think about an engineering career.
For more information, visit http://www.asq.org/manufacturing/why-quality/overview.html.
Baldrige Criteria--New and Improved The 2009-2010 Baldrige Criteria for Performance Excellence is now available. The criteria serves both as the standard for selecting the annual recipients of the Malcolm Baldrige National Quality Award and the road map for organizations worldwide seeking improved operations through innovation and performance excellence. Seven categories make up the criteria: leadership; strategic planning; customer focus; measurement, analysis and knowledge management; workforce focus; process management; and results.
The most significant revisions to the criteria are:
• An increased focus on customer (or patient/stakeholder or student/stakeholder) engagement. With the improved criteria, organizations can better assess their ability to deliver relevant programs, services, and products; develop a customer culture; and listen to the “voice of the customer.”
• An enhanced emphasis on core competencies that stresses their importance to an organization’s mission, strategy, and sustainability.
• A new consideration of societal responsibilities that explores how organizations contribute to the environmental, social, and economic sustainability of themselves and their community.
To date, 10 million copies of the criteria have been distributed since the first Baldrige Award cycle in 1988, and about two million copies are downloaded annually. For many organizations, using the criteria results in better employee relations, higher productivity, greater customer satisfaction, increased market share, and improved profitability.
According to a report by the Conference Board, a business membership organization, “A majority of large U.S. firms have used the criteria of the Malcolm Baldrige National Quality Award for self-improvement, and the evidence suggests a long-term link between use of the Baldrige criteria and improved business performance.”
The three editions of the 2009-2010 Baldridge Criteria--for business/nonprofit, health care, and education--are now available at http://baldrige.nist.gov .
For further information, visit www.nist.gov/public_affairs/techbeat/tb2008_1223.htm#baldrige.
It’s easy to assume that when the economy is in a recession, businesses will make major cutbacks in order to survive. However, according to the American Society for Quality’s (ASQ) latest Quarterly Quality Report, many manufacturing companies are not in the crisis mode one would expect.
In an effort to gain insight, ASQ talked with its members about the issue. The feedback clearly showed some of the expected pain companies are going through, such as reductions in work force, training, and budgetary cutbacks for quality initiatives.
However, the results displayed two very different types of organizations reacting in fundamentally different ways to eroding economic conditions. On the one hand, there are those going into crisis mode, cutting back, and de-emphasizing quality initiatives. On the other hand, there are those that continue to invest in quality and innovation as a competitive advantage in the face of economic uncertainty.
To cut back or to forge ahead when the going gets tough is the key question. Organizations that refuse to panic, that move ahead with new initiatives, and that don’t cut too deeply will be better positioned to excel when the economy rebounds.
“The really good news, if there is a silver lining in these times, is that while some companies are shrinking back into their shell, other organizations are moving decidedly in a forward-looking direction, and keeping quality practices at the top of the list,” says Ken Case, ASQ past president and emeritus professor at Oklahoma State University.
However, ASQ members that believed their organizations were in the midst of reduced viability, due to the deteriorating economy, were the ones that were much more likely to report reductions in work force, less training, and overall culture changes when it comes to business improvement where they work. Many were even backing away from quality initiatives that organizations typically use to cut costs.
In between the two obvious extremes is the middle ground of organizations that are attempting to balance efficiency with innovation and growth.
ASQ members said that waste reduction and efficiency are receiving a considerable amount of attention, along with efforts to generate inspiration and new ideas. Listening to the customer more and becoming more engaged in programs to bolster innovation and creativity are key toward continued growth.
Overall, many members felt that their companies and management were looking forward and using quality for long-term strategies.
The full Quality Report can be read at www.asq.org/quality-report/reports/200901.html .
Nicolette Dalpino is a news editor for Quality Digest.
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A Macquarie Island beach