Does nothing wrong mean anything right?

A couple of interesting papers recently crossed my desktop that I'd like you to reflect upon.

The first was a 1994 paper by Dr. Juran (one of America's top quality gurus) titled "Quality Problems, Remedies and Nostrums" that focused on the Zero Defect (ZD) movement. In this paper, he states that "the results of the ZD movement are not very impressive" first, because failures greatly exceed successes and second, published results appeared more qualitative than quantitative as if their main purpose was to impress their customers.

The second document is an ISO related discussion on the difference between "corrective action" and "preventive action" to eliminate the causes of non-conformance. The paper explains that corrective action is about stability, and preventive action is about capability. For QFD practitioners, this explanation also demonstrates the difference between a problem solving approach using DMAIC, and a design approach using DMADV to understand true customer needs and assure satisfaction.

Neither paper answers this critical QFD question, however: "Does nothing wrong mean anything is right?" 

We ask this question at the start of every QFD Green Belt^® course in order to provoke students to go beyond fixing and preventing negative quality, and to search for positive quality.

In other words, customers don't buy a product or service because the product is problem-free; they buy a product because it helps them, the customer, become problem-free. This means you must understand what outcomes the customer truly wants in their life and work.

 

Unfortunately customers are not always good at explaining themselves. After all, few suppliers ever bother to ask, so customers are not practiced at describing their problems or unfulfilled opportunities.

This is why VOC tools such as the gemba visits, Customer Process model, and Customer Voice table are essential to good QFD. These tools help customers use words and actions to show us what "success" means to them and why they are failing. Through these tools, customers can explain their biggest headaches and missed opportunities. 

With this knowledge, a QFD team can then identify solutions that are capable of delighting the customer better than the competitors. This is how QFD differs from other quality initiatives.

If you find this topic helpful, you might be also interested in reading "Finding Customer Delights Using QFD" in the 2006 Symposium Transactions. Better yet, plan to join us this fall in the 24th Symposium on QFD in St. Augustine, Florida, to learn more about these modern tools.

Romney PDCA

Mr. Newt Gingrich, in his 2006 book "Saving Lives and Saving Money", expounded on his decade-long fascination with Total Quality Management (TQM), six sigma, and lean thinking. Perhaps he could share his library with U.S. Republican Party presidential candidate Mr. Mitt Romney.

According to Romney advisor Beth Meyers who worked also on his 2003 Massachusetts governor transition team, Mr. Romney has his own brand of "problem solving" that might interest others in the quality field.

In an August 16, 2012 article in the New York Times, "Campaigning Aside, Team Plans a Romney Presidency" by Ashley Parker, Ms. Meyers is quoted:

“With Mitt, his approach to problem solving is first to identify the problem, make sure you’re solving for the problem actually there; second, look at best practices; third, apply best practices to the problem at hand; and fourth, execute on it.”

While Mr. Romney's four steps resemble Dr. Shewhart's and later Dr. W. E. Deming's "Plan-Do-Check-Act" approach to problem solving, it deserves some examination -- especially if he wins the election and employs this technique in government.

Let's compare the two approaches.

QFD is a PDCA approach.

SHEWHART / DEMING

• PLAN. Define the problem. This means to identify an undesirable state (problem) or a desired state (opportunity). How important is this problem relative to other problems. This requires deep analysis including:

1. Prioritization of problems and opportunities so that people, time, and money can be focused where they will do the most good. And by what criteria will "good" be defined? Is the problem due to common causes of variation or special causes?
2. Set a measurable target or outcome (how much must the problem be mitigated to be acceptable or how much opportunity must be realized).
3. What is the current state of the problem or opportunity.
4. What is preventing the current state from achieving the target. That is, what is the root cause(s) of the problem or missed opportunity. If there are many root causes, which has the greatest impact or correlation.
5. In order to address the root causes with the greatest impact, define what a good solution must do or be, independent of a solution.
6. Use creativity and innovation to propose solutions that will do or be what is defined in 5.
7. Define a way to test the solutions for efficacy.
8. Select the best solutions relative to efficacy, time, cost, and other considerations.

• DO. Test the best solutions to see how well they work in real application. Measure both the inputs of the solution as well as the outputs of the solution to determine if the results achieve statistical stability and not just luck.
  
• CHECK (also referred to as Study). Check the results of the solutions against the targets set in the Plan phase. Are they acceptable and sustainable? If not, search for new solutions or as a last resort, lower the targets (and be able to justify why, and when they will be raised again).
  
• ACT. Roll out the solution and standardize the improvements by issuing/training new operating procedures in order to prevent recurrence. Measure inputs periodically to assure that the procedures and systems are being followed. Measure outputs periodically to assure the improved process remains stable and predictable. Determine when the process will be reviewed for further improvement, or begin work on the next priority problem.
  There are many variations on the above, including DMAIC, but this will work for our discussion.
  

ROMNEY

• "Identify identify the problem, make sure you’re solving for the problem actually there." This sounds like good advice to make sure the problem is actually real. But, where is the analysis of the cause of the problem, the current state, the desired state?
• "Look at best practices." It is interesting that Deming did not care for benchmarking best practices, ridiculing the process as “the last stage of civilization.” His argument was that if your company is the same as others, why would your customers buy from you and not the others. Unique conditions require unique solutions. Where in this approach is creativity and innovation? (See our previous post "Benchmarking – the fatal flaw in modern quality thinking")
• "Apply best practices to the problem at hand." Where is the testing to see if the solutions are delivering the desired results? Where is the refinement?
• "Execute on it." This sounds like a repeat of "Apply best practices" so it is not clear if this adds anything to the process. Where is follow up to see if the solution continues to work?
  

Remember, that QFD is also a PDCA approach. Plan includes all the modern Blitz QFD^® tools up to and including parts of the Maximum Value table.

House of Quality matrix actually starts at the end of the Plan stage -- which is why it should be preceded with Blitz QFD^® anyway. Do is the design, development and prototyping. Check is the testing, and market validation phase. Act is the roll out, commercialization, product maintenance, and product retirement phase.

 

Which country won the 2012 London Olympics — Quantifying and prioritizing subjective data

The 2012 Olympics were fantastic and our British friends are to be congratulated on putting together a memorable experience for athletes and viewers alike.

But after each series of Games, whether summer or winter, I always marvel at the discussion of which country won.

Those of us in the quality field, for whom numbers are our bread-and-butter, may be interested to know that I posed this question to Dr. Thomas Saaty, creator of the Analytic Hierarchy Process, a method for quantifying and prioritizing subjective data. Tom, I'm not surprised, has authored papers on the subject.

Most news reports go for the straight count of medals:

1. The U.S. 104
2. China 87
3. Russia 82, and
4. Great Britain 65, for London 2012.

This assumes that all medals regardless of color, are of equal value. But what about other considerations, such as:

• What was the score difference between gold and silver (7 points in men's basketball, 0.12 seconds in men's 100 meter track, 0.100 points in a women's beam gymnastics)
• How strong was the competition (US men's basketball team were NBA professionals)
• How important is the event relative to other events (past modern Olympics included events such as hot air balloon [1900], poodle grooming -- actually this was an April Fools Day joke, and others.)

Dr. Saaty raises interesting questions to develop some weighting criteria, such as how long and difficult is the training, how many challengers in the world engage in the sport, and other intangibles. Saaty looks at additional factors such as national Purchasing Power Parity per person (Ethiopia wins 2008 with 161.441)  and country population from which to send athletes (Bahamas wins 2008 with 6.5433 medals per million people). He also raises the issue of how exciting the game is based on the average ticket price to spectators.

After looking at the medals from multiple perspectives in the 2010 Winter Olympics, Dr. Saaty settles on 7, 2, 1 for the values assigned to gold, silver and bronze medals respectively.

Applying this for 2012, he arrives at a very interesting observation:

1. The U.S. 104 total medals score 409
2. China's 87 medals score 342
3. Great Britain's 65 medals score 256, and
4. Russia's 82 medals score 251 -- creating a reversal for third place.

Those who want to know more are recommended to read the QFDI newsletter "Decision Making with AHP (Analytic Hierarchy Process)".

Today's quality professionals should know how to apply AHP in their projects for better analytic precision, and this includes six sigma black belts and anyone who is involved with prioritization of customer needs and product features in QFD. Case studies using AHP will be presented at the upcoming Symposium.

Social Media for VOC

In a recent New York Times article "Facebook, Twitter and Foursquare as Corporate Focus Groups" on July 30 2012, it was noted that producers of hit food and other retail fads are using social media to extract new ideas from consumers, as well as to select which ideas to commercialize.

Younger consumers who are more adept at online communications and can be attracted in larger numbers and more quickly than traditional focus groups. Further, their online profiles are self-populated and can provide much more demographic and attitudinal details than otherwise obtained. Sorting responses by these criteria can yield valuable insight according to age, income, location, and other characteristics important to target marketing.

In recent years, several QFD practitioners have been using social media to acquire Voice of Customer (VOC) data during new product development. QFD, of course, would usually begin well before focus groups were employed to evaluate solution options, in order to acquire VOC to define customer needs and product requirements. In these cases, users are asked to send in videos and photos of their activities and frustrations, usually around a product theme. Other uses are to search personal social media postings for issues related to the new product project.

In my experience, this has proven to be a rich source of candid VOC where the user is directing the script. A kind of virtual "gemba." In one case, we uncovered that one company's product was being abused by young teens, allowing the maker to change the product and make it less prone to tampering.

Of course, like any customer gemba data, these are only inputs to a deeper QFD analysis that includes translating VOC into prioritized customer needs, product requirements, and features. These features can be tested again using social media as described in the above captioned article.

Benchmarking – the fatal flaw in modern quality thinking

Frequently we hear in quality conference presentations and papers high praises for benchmarking and "shamelessly stealing" the ideas of others. But does it make sense to take what is successful elsewhere and expect it to work in a different context with different staff and customers? Two recent news reports are noteworthy.

"How Apple Store Seduces You With the Tilt of Its Laptops" (from Forbes Magazine, June 14, 2012): Apple Retail has found that tilting demonstration laptop computer screens at a specific angle encourages customers to adjust them to their ideal viewing angle – and by virtue of touching the computer, invite them to experience the product and its apps in a multi-sensory mode.

"A Store Without a Checkout Counter? JCPenney Presses on with Retail Revolution" (Time Magazine, July 20, 2012): In late July 2012, J.C. Penney (a large American department store chain) announced that by 2014, it will eliminate cash registers and checkout counters at their retail stores. This idea emulates Apple Computer's successful retail store format, also the brainchild of Ron Johnson who left Apple Retail this spring to become CEO of J.C. Penney (JCP). Key functions of the plan are to have store employees with remote scanners roam the store and record purchases and payments, as well as create an iPhone app that allows customers to check themselves out.

Readers who have shopped at an Apple Retail store know that you are surrounded by staff both eager to leave you alone to play with the devices, but instantly there should you have questions or wish to make a purchase. If you use a credit card, you can be immediately checked out right where you stand, and instantly receive your receipt by email. But can a clothing and general merchandise retailer imitate this successfully?

From a QFD perspective, let's examine JCP's decision to emulate Apple as a new solution to an existing problem or opportunity. At the start of a technology-driven QFD project (Apple may have been customer-driven, but benchmarking is usually technology- or solution-driven), we look at the the functions of the technology and what important customer problems does it address?

For example:

• Who are the target customers and how do they shop?
• Do they come in with a purchase already in mind or do they browse?
• Do they buy things from multiple departments and don't mind paying for different purchases in different departments?
• Do they pay with cash?
• Do they add additional items as they walk towards the checkout counter?
• How big a problem is checking out and purchasing at JCP today?
• Do customers abandon their purchases due to waiting in line?
• What other problems do customers face at JCP such as poor selection or size availability?
• How will floor staff handle lost sales when customers that cannot find what they want?

So, when benchmarking another business, be careful to understand the "spirit" and not just the "form."  We talked about this in the QFDI Newsletter "Hoshin Kanri - Understanding the spirit behind the form"

What fits others may need alterations before it fits your business.

When executive solutions become design constraints #2 – The case of Sweden's 17th century warship Vasa

In my last blog, I related the case of the boss who did not listen, and actively discouraged the advice of the very specialists he hired. An historical, but famous example of this recently came to my attention.

In a recent onboard flight magazine, I came across an article recommending things to do in Stockholm. Among the list was the Vasa Museum. I remember visiting it on one of my earliest QFD trips to this beautiful Scandinavian country. It was impressive to see the fully intact 135 foot wooden warship from the 17th century despite it being lost under water for over 300 years.

From my QFD perspective, the ship’s history offered interesting insight to the management style problem discussed in “The unreasonable boss - when executive solutions become design constraints.”  

Vasa, fully intact 17th century Swedish warship
(photo - wikipedia)

Vasa was commissioned by King Gustavus Adolphus (1594–1632) to flag the nation’s largest and most powerful naval force at the time. But immediately after leaving the dock on its maiden voyage in 1628, the ship sank in the Baltic Sea.

Why? Too many design changes as after-thoughts, lack of specifications and documentation detailing the ongoing design changes and modifications, unclear division of responsibility, unrealistic schedule demand, the project mission that got blurred by those changes, and stunted communication between the customer (king), producer (shipwright and builder), and operator (naval officers in charge of testing and navigation).




In particular, the changes that the king ordered after the timbers had been cut to size and the ship’s keel had been laid exacerbated the ship’s instability and ballast deficiency. Other late changes also shifted the project mission unwittingly.

For example, adding the second gun deck (after learning Denmark was building such a design) not only increased the weight burden (too many cannons) but also changed the main objectives of naval war tactics (from crippling the enemy ship with firing volleys from one deck and taking over onboard to capsizing the enemy ship by broadside firing from two decks).

decorated stern model of Vasa
(photo - wikipedia / Peter Isotalo)

In those days it was customary for warships to have ornate decorations that glorified the king. Again, many more sculptures were added on Vasa than its original design. Each measuring 10 feet long, you can imagine how heavy 500 sculptures were to the 135 foot ship.

None of the workers and subordinates had the courage to reveal these structural problems to the king, who had issued a threat against anyone causing schedule delay.

As we discussed in our previous post, Modern Blitz QFD^® tools can help analyze and offer solutions to these scenarios.

Readers, can you follow the process described in that post and do your own analysis of the advantages and disadvantages of the king’s orders for the Vasa project?  Please share your analysis and questions with us in the comments.

The unreasonable boss - when executive solutions become design constraints

An acquaintance of mine recently complained that her new boss just didn't listen. She was recently hired by a large sports wear chain to manage their social media and promotional events in advance of their entering new markets and attracting new customer segments.

The owner, it seemed, was so attached to his ideas of how to promote because of his past successes that he could not comprehend that the new customers he wished to attract needed to be approached differently. His most recent demand was that because his children liked popcorn, he told the marketing team to rent an old-fashion popcorn cart for the product booth at a street fair in 100°F weather.

What bothered my acquaintance most, however, was that her direct boss and other managers were afraid to challenge the owner's positions. Whatever he demanded, he got.

QFD has some solutions to such a scenario. Whether it is the boss or the customer, proposed solutions need to be translated back into functional requirements, and then into solution-independent needs, so that better solutions can be examined to achieve those needs.

In the sports wear store example, the popcorn is a solution to what problem or need? Can we analyze for the owner the advantages and disadvantages of popcorn.

For example:

Popcorn's aroma attracts attention. Functional requirement: Attract attention. Need: Our booth stands out in a crowded event. What other ways can we stand out on a hot day? How about misting fans? Handing out folding fans?

Popcorn is something kids love to eat. Functional requirement: Distract kids. Need: Keep kids entertained while mom looks at our sports wear. How else can we entertain kids on a hot day? How about water guns?

Popcorn from an old-fashioned cart shows we are traditional and have been here a long time, and will continue to be here a long time in the future. Functional requirements: Show we are your neighbors and a trusted part of your community. Need: We are a trusted place to shop. How else can we build trust in this new market segment? How about our brands, satisfaction guarantees, our current customers who are respected in the community?

Food sales require a city license, trained operators, food handling protocols. This is a constraint that makes it expensive and time consuming. Our focus is to sell sports wear, and the popcorn could be a distraction.

Popcorn oil can damage our sample products. Kids and adults eating the popcorn and then touching the products will leave fingerprints and stains that will make our samples unattractive and discourage potential shoppers. This is another negative.

If you have attended a QFD Green Belt^® course, you remember that this solution-to-need translation is the job of the Customer Voice table and that the analysis of solution constraints is the job of the Maximum Value table.

Both are new tools  in Modern Blitz QFD^®. These are core tools in the QFD Green Belt^® Course offered in St. Augustine on October 21-November 1, 2012.

“Learning is not compulsory, neither is survival.”

A civil revolution is taking place in one of the world’s most politically stable places, Japan, whose citizens are known for social conformity and respect for authority.

Tens of thousands of ordinary Japanese are filling the streets of Tokyo and other cities, not just for a day or two but for weeks now. They are protesting against the government’s decision to re-start the nation’s nuclear power plants, following the multiple nuclear core meltdowns in Fukushima last March.

On June 29, 2012 alone, 150,000 to 200,000 marchers surrounded the prime minister residence, according to a major Japanese newspaper Asahi Shinbun.

The Japanese government and industries want nothing more than a quick recovery from last year’s natural disaster-turned major nuclear catastrophe. So they are pushing for a rebuilding of the disaster-stricken region and restoration of economic/industrial output through conventional means, which include re-starting the nation’s nuclear power program.

But this return to “business as usual” approach is too reckless, the protesters say, because the nuclear plants are being restarted with unprecedented fast-track approvals that ignore the lessons of Fukushima. Indeed, a leading seismologist from Tokyo University says some of these nuclear reactors sit right next to the “Devil’s Triangle” where the northern and southern halves of Japan’s crustal plates meet.

Could another nuclear plant accident resulting from earthquakes occur in the near future? In Japan, where nuclear power comprised nearly 30% of electrical production, what is the best next step for economic production, civil activities (trains, air conditioning, etc.), and safety for future generations?

Here in the U.S. heartland, as we endure the sweltering, record-breaking summer heat of over 100°F and multi-day power outages, we can appreciate the concern of all sides in Japan. How do we choose between the stable availability of air conditioning vs. a decades- and centuries-long threat of radiation to our air, food, and water? Do we accept compromise and trade-offs, or are there new ideas? Do we have the necessary innovative vision and strong leadership? We quality practitioners have wrestled with this dilemma for decades.

Dr. Deming famously said:

“It is not necessary to change. Survival is not mandatory.”

“Learning is not compulsory, neither is survival.”

Just a few days ago, the Japanese once again rose to Dr. Deming's challenge. Its parliament released a Fukushima study that identified the physical, procedural, and regulatory safety flaws, and concluded that the Fukushima nuclear incident was “profoundly man-made” by the negligence of the plant operator and the culture of face-saving, non-transparency, regulatory collisions, and exclusion of opposing views, all of which exacerbated the severity of the incident.

These challenging times, Dr. Deming would say, require innovative vision, breakthrough changes, and a leadership of courage.

In QFD, breakthroughs can come from both technology advancements and a better understanding of solution-independent customer needs. Also, when designing for a project like a nuclear power plant, it is important to anticipate the low-probability high-consequence risks that traditional FMEA does not handle well (see How To Handle VOC Issues — Lessons from Japan crisis: Anticipating Improbables with Irreversible Consequences).

In the short-term, the people of Japan are becoming more vocal in their needs and demanding providers (including the government and energy companies) be more innovative in their thinking and responsive to citizens and customers, respectively.

Japan is realizing it must learn and it must change. Their survival depends on it.
All our survival depends on it.

 

Our QFD Community – a home for young professionals and scholars from around the world

One of the pleasures of the QFD Symposia is the chance to meet young professionals and scholars from around the world. We'd like to share some of their stories as a way to invite readers of this blog to join our community as a presenter, writer, or attendee.

The opportunity is best explained by this mail we received recently from Dr. Francisco Tamayo-Enríquez, one of our colleagues in Mexico who, after earning his Ph.D.,  was named in the November 2011 issue of the American Society for Quality's Quality Progress magazine as one of the top young professionals making a true quality difference in their organizations.

”(the word) ‘Sharing’ in Spanish means not only to inform, but also to express gratitude.  I need to recognize that the beginning of my “international” career was because of the enthusiasm and support that I received from the QFD Institute and QFD community. Therefore, this recognition is also to the QFD community that had supported me during all these years and allowed me to have a lot of satisfactions and professional growth. Thank you very much sensei (teacher), for this invaluable opportunity.

"I owe a lot of my recognition to my QFDI community, teachers, workmates and students. To be able to stand in front of an international, English-speaking community, to write technical papers, to be able to participate and lead in modern-correct-useful QFD projects and to teach my students." 

Another QFD colleague from Mexico, Verónica González Bosch, was also recognized in the ASQ magazine's top young professionals list. Verónica received the Akao Prize® in 2006 and runs the Spanish language QFDLAT.com website.

These messages speak to the community of all QFD professionals to support our next generation of QFD experts. How can we help?

Beyond the formality of paper presentations, the Symposium is a forum of idea exchange and mutual learning. It offers an opportunity to see real world applications as they happen, something way beyond what is covered in textbooks. More important, it offers an opportunity to network with and get feedback from experts on QFD implementation, research, which tools to use, and even thesis guidance.

Over the years, we've met many talented young people from all over the world through the Symposium. For example, one Ph.D. student from Serbia, Dr. Miljan Radunovic, contacted us a couple of years ago. Through a series of emails, we encouraged him to write up his situation. At the 2011 International QFD Symposium in Germany, this young man identified himself, saying that the paper we persuaded him to write not only got him accepted for the Symposium and earn his Ph.D., but also landed him a good job right out of school and a sponsorship to travel to the Symposium.

Dr. Catherine Chan was another Ph.D. student with a serious dedication. She wanted to help the Hong Kong clothing and textile industry transform their traditional OEM business model into a more competitive global player. Her first QFD paper, using classical QFD tools, was presented at the 2005 International QFD Symposium. Since then, she has taken up every opportunity to learn Modern QFD, first enrolling in the QFD Green Belt® Course and eventually earning her full-status QFD Black Belt® this year. She now heads the Hong Kong QFD Association and teaches at Hong Kong Polytechnic University.

In the 1990s, we got to know Dr. Fatih Yenginol, a young scholar from Turkey, when he first attended the QFD Symposium in Michigan, and later as a student in the advanced QFD courses, and finally as a speaker. He laid the foundation for QFD education at his Dokuz Eylul University, organizing their first Turkish QFD Symposium in 2002 and later posthumously receiving the Akao Prize® in 2005. Although illness cut his life short at a young age, his legacy has been passed down to successive generations of scholars at the university, who hosted the 2005 International Symposium on QFD and additional QFD Green Belt® courses for Turkish industry. Dr. Aysun Kapucugil Ikiz, also of Dokuz Eylul University received an Akao scholarship, as well.

Other students in our QFD community have become a specialists in their own fields. We met Dr. Anders Gustafsson also at a U.S. QFD Symposium many years ago when he traveled from the Linkoping University in Sweden where he was a Ph.D. Student. He was instrumental in bringing the Third International QFD Symposium there in 1997. Anders is a recipient of the 1999 Akao Prize® for QFD, and he has gone on to become a leading scholar in the field of Conjoint Analysis.

These are some of the young talents who grew up in our QFD community and have gone on to great careers. If you are or know someone like them, we invite you to come see us at the upcoming QFD Symposium in St. Augustine, Florida on November 2, 2012.

If you wish to be a speaker, we invite you to send an abstract. To learn the best practice tools and methods of Modern QFD, we recommend attending the QFD Green Belt® Course offered at the symposium.

Big Soda and Obesity Fishbone Analysis

New York City mayor Bloomberg made headlines recently by proposing a ban on the sale of sugary soda that is larger than 16 ounces (473 milliliters). He explained it as “a way to fight obesity in a city that spends billions of dollars every year on weight-related health problems.”

The mayor’s proposal is stirring up a myriad of debates, from anti-junk food / sugary drink movement, freedom of choice, food stamp, school lunch program, political motive to healthcare cost management, universal health care, and legislative legality. “What’s next on the list? Large slices of pizza? Double-scoop ice cream cones? Tubs of movie-theater popcorn? The 16-ounce strip steak?” asked a newspaper.

Well, obesity is a national problem. According to the CDC, an estimated 30 percent of U.S. adults (over 60 million people) can be classified as obese. One study said that obesity adds $190 billion in the nation’s health cost [msnbc.com 4/30/2012].

We applaud the mayor’s good intentions and willingness to tackle the obesity problem. But obesity has so many causes. Is the oversized sugary soda the major one?

So here we‘ve tried a simple quality tool, a fishbone diagram.

What comes next is further studies to determine which cause has the high contribution to obesity and what would be the most effective and efficient solutions to address this cause.

But until the mayor can prove that an oversized sugary soda indeed has the highest contribution, the proposed soda ban may only have a minimal effect on the war against obesity.