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Wednesday, March 9, 2011

Correlation and Cause: Does Walmart make you fat?

I just learned of a study analyzing the presence of Walmarts and obesity rates.

You can download the entire paper but at least read the abstract carefully. At one point the author says one variable "explains" the other. But just before that, he says one variable "increases" the other. Claiming that one variable increases another is a much stronger claim than "explains" and largely implies "cause".

Do you think that a causal claim is appropriate? Will building more Walmarts really make people fatter or can something else explain the association?


  1. I do not believe that making a causal claim is appropriate. Just because Walmart offers lower prices on food does not mean that it will make people fatter. The reduction in food prices is not just for unhealthy food. It has reduced prices on every type of product in the store. It is the decision of the consumer on which and how much food they buy.

    Building more Walmarts in the area does not "increase" the BMI of a person or obesity percentage, even if there is a correlation. There are many other variables towards why the obesity percentage has been increasing throughout the years.

    Such as amount of exercise, type of food they eat, how much they eat, when they eat, etc. There could most likely be a fast food chain near the Walmarts. That could be another variable.

    I just do not see there being a direct cause for Walmarts making people fatter.

  2. Agreeing with the previous comment, I notice a lot in Wal-Mart ads in the stores they will headline their store brand products, Great Value, because of lower prices than private label brands. The thing with Great Value is that they don't produce organic products because their main objective is to sell generic product at a discounted price. Also, walking through Wal-Mart stores, they have poor placement of health products besides having a fruit and vegetable section in the front of stores.

    Another thing to take into account with every new Wal-Mart store there is one or two or more fast food restaurants within less than a quarter mile. By the Wal-Mart in my hometown there is a Culver's, Popeyes, Arby's, and Subway. Are tendency to implusively eat should be a better indicator to our obesity than having more Wal-Marts built.

    Implusiveness could be a possible lurking variable if you truly think about it

  3. I some what disagree with the above comments. There might be a weak correlation between Walmarts and BMI's, but there is some causation behind this. Walmart sells food at a discounted price and they make it very convenient for people to get in and out of their stores fast. Walmart used to be not on the map for selling groceries but now they are the largest seller of them. They offer their brand at a discount price, which is appealing to the poor. In todays society it cost more to get a healthy meal than to get a cheap fast food meal. If you combine the two with cheap and non healthy food it leads to eventual obesity.
    So building more Walmarts will increase obesity because it offers a cheap substitutes and fatty foods, with the main word being convenient for customers.

  4. I think this is a classic example of how statistics can be used to prove almost any point you want to. It is possible that the presence of Wal-mart may cause obesity. However this article's abstract doesn't show any concrete correlation between the two. At best it shows that Wal-mart is a contributing factor to raising obesity rates. I think that you will also find that increase industry and urbanization increased at the same times that the wal-marts were built. I think this would also have an effect on obesity rate given that industrialization and urbanization lead to less free time for activity and cooking which means people spend less time burning calories and less time preparing healthier dining. I would also guess that fast food chains increased in the area in either numbers or profits of existing ones.

  5. I agree with the above post. I think it is irresponsible to claim that increases in Wal-Marts cause an increase in obesity. As Tarble 3 Long pointed out their very well could have been an increase in urbanization. An increased urban population means that more stuff is built and places become more spread out, and this can cause people to drive more and walk less. Therefore it is reasonable to assert that obesity and Wal-Marts are caused by the same underlying variables.

  6. I agree with Lierman on the point about irresponsibility. While it may be true that there is a correlation between the number of Wal- Marts and obesity cases, we cannot conclude that Wal- Mart causes obesity. In those same Wal- Mart stores where food is sold cheaply, organic food is also relatively cheap compared to other stores and customers can choose that instead. It is also very irresponsible to over eat just because the food is cheap. An obese person who uses this reason as a defense is just looking for an excuse.
    It may be true that the growing presence of Wal-mart has somewhat increased obesity cases,there could be other reasons for this such as lack of proper nuitrition education, laziness to exercise, or busy lifestyles leading to regularly buying take outs from fast food restaurants.

  7. The way I think about it is kind of different. I'm looking at Wal-Mart as a global MNC and their position within the retail markets. We all know WM has grown not only as a company but their stores have gotten increasingly bigger as well. Their stores carry EVERYTHING. They have so many brands of products, including ones that are probably not so healthy for us to eat. Their billionaire status as a company requires them to fill their humongous stores with so much product, most of which, wont even be touched by wal-mart shoppers. All this product in their stores can also be placed in certain focus areas, paid for by the products marketing and advertising divisions. I feel their are too many lurking variables lying around for their to be a causation like that. just my thought. I can see how their would be a moderate correlation though.

  8. My take on this topic is kind of along the same lines as Maureen. Wal-Mart does sell fatty foods for cheap prices, HOWEVER, they DO sell healthy foods for cheap prices as well. It is up to the CONSUMER to choose what they want. In the essay, the author says that, 11% of the rise of the obesity rate since the late 1980's was Wal-Mart's fault, when in actuality, even if Wal-Mart didn't exist the obesity rate would still go up and the 11% would come from another grocery store/retail store. It just happens that Wal-Mart is everywhere. People have to get their food from somewhere, whether a target or your local grocery store, it's still not going to change what they eat and how they eat it. Honestly, American's have gotten lazy, food in America before the late 80's were just as bad or even worse than now, and in present day we have way more alternatives. Just because you can get cheaper food at Wal-Mart(which unless your getting a ton of food, your not really saving THAT much) doesn't make it O.K. to be a couch potato.

  9. They can not allocate 11 percent of the rise of obesity to Walmart. It is one of the many large companies/fast food industries that sell fast, convenient food that happens to be not good for you. This however, doesn't mean that it is Walmart's problem, but more the society that we live in and the trends of food that is being sold cheap. Walmart is the one that is getting picked on because it is the retailer that is extremely successful and all its competitors want to be like. It isn't selling "illegal fatty foods" that other companies cant sell. They are selling the same goods, just more of them and are better at it. Just because they did everything right doesn't mean they forced the customers to buy more than their share of the unhealthy food. It is not only ridiculous to blame this rise on a company instead of the consumers, but to also pick Walmart as the scapegoat for the large industries marketing campaign and sales.

  10. As we have discussed throughout the semester, correlation does not equal causation. There are many variables that need to be looked at for this data. The main one I see is the population size of the towns and cities that Walmart's are being built. If the population is bigger or smaller then that could sway the average weight of the area where the Walmart is. Where a Walmart is built usually means that the population of the community there is growing, so maybe people who weigh more are moving in to these communities.