Did McDonalds cause the decline of violence in America?

Violent crime has been on the decline in the US since 1990, and largely, the reasons for the decline have been inexplicable. Steven Leavitt (of Freakonomics fame) and John J. Donohue III argue that around 50% of the reduction in crime is the result of earlier introduction of legalised abortion (PDF). I’ve got a theory – and it is just a theory at this stage – that McDonalds in the US was also a causal factor in the decline of violence.

Over the last decade Cdr Joseph Hibbeln has been researching the link between violence and the consumption of omega 3 fatty acids. From the Guardian:

Over the last century most western countries have undergone a dramatic shift in the composition of their diets in which the omega-3 fatty acids that are essential to the brain have been flooded out by competing omega-6 fatty acids, mainly from industrial oils such as soya, corn, and sunflower. In the US, for example, soya oil accounted for only 0.02% of all calories available in 1909, but by 2000 it accounted for 20%. Americans have gone from eating a fraction of an ounce of soya oil a year to downing 25lbs (11.3kg) per person per year in that period. In the UK, omega-6 fats from oils such as soya, corn, and sunflower accounted for 1% of energy supply in the early 1960s, but by 2000 they were nearly 5%. These omega-6 fatty acids come mainly from industrial frying for takeaways, ready meals and snack foods such as crisps, chips, biscuits, ice-creams and from margarine. Alcohol, meanwhile, depletes omega-3s from the brain.

To test the hypothesis, Hibbeln and his colleagues have mapped the growth in consumption of omega-6 fatty acids from seed oils in 38 countries since the 1960s against the rise in murder rates over the same period. In all cases there is an unnerving match. As omega-6 goes up, so do homicides in a linear progression. Industrial societies where omega-3 consumption has remained high and omega-6 low because people eat fish, such as Japan, have low rates of murder and depression.

[note: link added by me]. Apart from flaxseed oil, canola oil has the lowest ratio of omega 6 to omega 3 of the vegetable oils at about 2:1. Beef tallow has a omega 6 to omega 3 ratio of 6:1. In 1990, when violent crime hit its peak in America, McDonalds stopped using beef tallow in its fryers and switched to (mostly) canola oil – and as far as I know – almost all American fast food chains followed suit. This certainly increased the total intake of omega 3s and the ratio of omega 6 to omega 3 amongst all Americans who eat a french fry-heavy Standard American Diet. Find out more right here kostenlosepornos.live.

Exactly the same trend followed in the UK. McDonalds replaced beef tallow in the mid-90s, and and since then, the UK has seen the number of victims of violent crimes halve.

They’re interesting correlations but I can’t find (or at least, don’t have the time to find) better data to come up with anything approaching causality.

Any economists want to pick up the baton from here? Anywhere that I can get good datasets on per capita canola oil consumption?

Have we hit peak food media?

Adweek gives us a resounding maybe:

The sheer number of choices is overwhelming, which may be why there’s been some slippage in the TV landscape: Food Network’s Nielsen rating slipped 4 percent year-over-year, Top Chef’s most recent season premiere drew 1.66 million viewers, down more than 1 million from the series’ highwater mark of season five, and Every Day with Rachel Ray magazine lost 14 percent in ad revenue from last year, according to the MPA, Association of Magazine Media. And critics say the glut of reality-show competitions associated with cuisine has cheapened the culinary landscape. The field is becoming so crowded, goes the argument, that food media is being pushed to absurd extremes.

According to Adweek, there are currently 11 reality shows devoted to cupcake and cake. How much food media is too much for the public to bear?

Do online consumer reviews affect restaurant demand?

One of the more difficult questions in social media is the degree to which online reviews impact upon the bottom line of businesses; and whether bad online reviews cause declining patronage. Harvard Business School’s Michael Luca says yes, and very much so [PDF]. There is not only an impact, but that impact is causal:

Do online consumer reviews affect restaurant demand? I investigate this question using a novel dataset combining reviews from the website Yelp.com and restaurant data from the Washington State Department of Revenue. Because Yelp prominently displays a restaurant’s rounded average rating, I can identify the causal impact of Yelp ratings on demand with a regression discontinuity framework that exploits Yelp’s rounding thresholds. I present three findings about the impact of consumer reviews on the restaurant industry: (1) a one-star increase in Yelp rating leads to a 5-9 percent increase in revenue, (2) this effect is driven by independent restaurants; ratings do not affect restaurants with chain affiliation, and (3) chain restaurants have declined in market share as Yelp penetration has increased. This suggests that online consumer reviews substitute for more traditional forms of reputation. I then test whether consumers use these reviews in a way that is consistent with standard learning models. I present two additional findings: (4) consumers do not use all available information and are more responsive to quality changes that are more visible and (5) consumers respond more strongly when a rating contains more information. Consumer response to a restaurant’s average rating is affected by the number of reviews and whether the reviewers are certified as “elite” by Yelp, but is unaffected by the size of the reviewers’ Yelp friends network.

It is pretty grim news, if you’ve spent the last hundred or so years building up the strength of a chain restaurant’s brand, only to find that increased reviewing is replacing your hard-earned equity. The recognition that certified reviewers actually do have a greater impact in systems like Yelp raises further questions whether these “elite” users follow the crowd or lead it. Duncan Watts and Matthew J. Salganik have done some great research into this, in which perceived success of cultural products online translates into actual success regardless of content, so it is altogether possible that people who contribute online reviews continually reinforce each others reviews for the good or ill of businesses.

Hat tip to Adam Ozimek from Modeled Behavior for the article.