Tuesday, September 22, 2009

WISQARS Suicide Statistics - Part II

In Part I I started to explore who was committing suicide and why gun control efforts to use this issue to support their cause were worthless. One of the major themes I mentioned is that men and women are different. This should come as no suprise to anyone. Even a five year old from the movie "Kindergarten Cop" knows this. So let me look more at how people choose to commit suicide and what it might tell us. Some things to remember from last time, men commit suicide more than women. Older men commit suicide at a much higher rate than any other group. My goal here is to show that suicide is a much larger issue than gun control groups make it out to be and simple "solutions" like limiting access to guns are not going to affect it.

Some have argued that guns mixed in with suicide result in more deaths. Somehow, guns are more lethal than other methods of suicide. I introduced my lethality ratio in the last part. This shows which methods of suicide end up being the most lethal.
Clearly, drowning and suffocation are far more effective methods than firearms. Even fire is more effective in the later years, the group that has the highest suicide rate. Are women any different?
Similar but not the same. drowning and suffocation are almost univerally lethal across all groups. In later years, fires and falls become more lethal. Firearms are as lethal for some age groups, but by and large other groups have less lethality than males.

Overall, what this is telling me is that there are already plenty of other methods that people use to commit suicide that are are just as lethal or more lethal than firearms. Removing them will not decrease the suicide rate.

What are the major methods people use to attempt suicide? Poisoning and Cut/pierce. This is telling because if we are going to propose "limiting access" to some object as a means to decrease suicides, then limiting access to poisons and sharp objects is an impossible task. They are literally everywhere and completely unregulated. While poisoning may have a relatively low lethality rate, the fact that orders of magnitude of people attempt to use it results in a significant number of suicides. For women, more suicides occur from poisoning (1.69 per 100000) than firearms (1.43 per 100000). The vast majority of attempted suicides are by poisoning for men (63.01) and women (96.32). The number two method, cut/pierce, is a distant second (23.71 men, 25.29 women). Firearms is an even more distant 3rd. So any attempt to limit the methods of suicide is going to be fruitless. We live in a world that is full of things that are dangerous. The average household has enough chemicals that if distributed appropriately could kill 10,000 people.

Serious researchers of suicide know all of this. Limiting access to methods of suicide are only effective if someone is with the suicidal person - it is a full time job. That is why they advocate not leaving someone alone who has expressed suicidal tendencies. Stay with them constantly, and get professional help. In that order. If you believe that "limiting access" to objects through legislation is effective, continue living in your fantasy world. Just don't be surprised when people like me call you out for the waste of resources you have perpetrated and let you know that you haven't saved a single life.

WISQARS Suicide Statistics - Part I

Suicide is an issue that ends up being marginalized by those who are in support of gun control. It is a fact that about half of successful suicides in the US use a firearm (16,800 out of 33,200). Those in favor of gun control like to lump these in as part of gun violence since it helps to inflate their numbers (especially since there are only 13000 gun homicides and 700 accidental deaths each year). In previous posts I have said and in some cases shown data to identify that the underlying causes of these three problems (crime, suicide, and accidents) are not related. Therefore, effective solutions to them will be different. So let me examine suicide for a bit.

The source of my information is the WISQARS database (both death and injury) for the years 2001-2006. The first problem that gun control groups run into is combining age groups. Here is an example from the Brady Campaign:
"In 2006,16,883 U.S. residents killed themselves with a firearm, including over 2,000 young people (ages 10-24) (National Center for Injury Prevention and Control (NCIPC))."
Their definition of young people (not the NCIPC's where they get their information) is ages 10-24. I can't argue that the age range is considered young, but if that is the case, then why not include 0-24? To me, 0-19 might seem more appropriate. In any case, let's apply some critical thinking to the numbers. 2000 out of 16883 is roughly 12% of all suicides. If we assumed an even distribution of ages between 0 and 75, then the group in question (10-24, 15 years) is 20% of the age distribution. So, on the surface, it would about that this portion of the population (10-24 year olds) is less likely to commit suicide with a firearm than the population as a whole.

Now lets take it a step further, we know that people are not evenly distributed by ages, there are less 65-80 year olds than there are 0-15 year olds. So if the 15 year span, had significantly fewer (i.e. lower percent) of people than other 15 year spans. Except it doesn't. Demographic data for the US, confirms that there are about 60 million people in each 15 year age span up to about age 60. After age sixty, the number decreases by about 20-30% for every 5 years. In other words, the 10-24 age range actually represents more than 20% of the population, so they are even less likely to commit suicide (in spite of the horrific teen years) than the rest of the population.

Let's look at it another way, why not include all young people, everyone from 0-24. Does anyone think that 0-9 year olds will add a significant amount of suicides to the 2000 there are already for 10-24 year olds? I didn't think so. I would add 50 just to be fair. So 2050/16,883 , still 12% are now committed by something north of 33% of the population. That would mean young people are still even less likely to commit suicide. In case you haven't noticed, it is looking like suicide is not primarily a young person problem. Whereas the majority of gun crimes are committed (and perpetrated against) 15-24 year olds, not even a significant portion of suicides (only about 12%) occur to people in the "young person" category. This tells me that this argument is primarily a sympathy plea. We all look at children as innocent.

At least the Brady Campaign doesn't say that 24 year olds are children, but I wonder what the stats would look like if say the 20-24 year olds were removed. Good thing they included the statistics here. So, almost 1300 of the 2000 firearm suicides are from the 20-24 year old age group. Knowing this, it really puts a much different spin on suicides. 0-19 year olds ("children") make up more than 25% of the population as a whole. However, they are only responsible for 4.5% of firearm suicides. Or they are 5 times less likely to commit suicide with a firearm than the population as a whole. To me, that sounds like this age group is emminently trustworthy with firearm (but that would be committing a logical error by not accounting for the availability of firearms to this group of people, so I won't conclude that). What it does tell me is that compared with the rest of the population children committing suicide by firearms (and committing suicide in general) is not a major problem. Tragic? Absolutely. But do we need to take drastic measures for every tragic incident? If so, then life will come to a standstill as we try to "prevent" tragic incidents.

The next major problem that gun control groups make is trying to simplify a complex issue and apply a "solution" that won't fix anything. One of the solutions to "children" committing suicide with firearms is safe storage laws. In a nutshell, safe storage laws require some method of securing firearms such that "children" wouldn't be able to get to them. In some states with these laws, parents can be held criminally responsible for crimes (including suicide) that are committed with firearms they didn't "properly" secure. As we have seen above, less than 5% of firearm suicides are committed by children. Since the age range of 0-19 has an overall suicide rate per 100,000 of 2.26 and a firearm suicide rate of 1.02, someone in the 0-19 category is more likely to choose a method other than firearms to commit suicide. So, will "safe storage laws" prevent suicides? Most likely not, other means are available, and just as effective. They definitely have the potential to ruin a family more by charging the parents with criminal negligence when they are already dealing with the suicide of a child.

So, if suicide is not a "youth" problem, where should our efforts be focused? One of the things that the quest for "equality" has done is blur and in some cases erased the idea that there are differences in people. Men and women are not alike. Blacks and whites are susceptible to different genetic diseases. Old and young act differently based on any number of factors. Part of coming up with solutions to problems is to realize that we are not all the same. The second is that government is rarely the solution to any problem. You can't legislate solutions. Government "solutions" could be described as a band aid, and more likely as a butterfly band aid. It may hold the wound shut, but it won't stop the bleeding, and it definitely doesn't fix broken bones.

Here is a simple chart of who is committing suicide and who is attempting to commit suicide broken out by gender and age. Solid lines use the left axis, dashed lines use the right axis.
Some things to take away from this graph. First, males are more likely to attempt suicide and commit suicide. The greatest disparity is in committing suicide though. Besides a narrow time period (15-19) males and females attempt suicide at the same rate. However, males are far more likely to commit suicide than females, 5 to 10 times more likely. Second, young adults (15-24) attempt suicide more often than the general population, however, it also results in injury rather than death at a higher rate. This would seem then to be a plea for attention or help rather than being serious about ending one's life. Third, there is a disconnect between the stable rate of attempted suicides (25-44) and the stable rate of suicides (20-65). As a part of this it should also be noted that there appears to be a peak in suicides around age 45-49 (mid-life crises?) for both men and women. Fourth, after age 44, men and women are nearly identical for attempted suicides. However, fifth, after age 65 men and women vary greatly in committing suicide: women have a stable to decreasing rate, men on the other hand have a steadily increasing rate.

Suicide as a method of death, isn't even an issue until someone is into their 20's. That doesn't mean we should ignore it, but compared to the rest of the population, our focus should be elsewhere. Let me end this part with one more graph. The Lethality Ratio. The lethality ratio is the rate of suicide (death) divided by the rate of attempted suicide (injury) to determine what group is more likely to die.
Clearly, older males are far more adept at killing themselves. This is one reason why whenever someone brings up suicide as a reason for more gun control, especially targeted at "children", I know they are disingenuous. They are only trying to pull at heart strings to get their power trip. All the gun control in the world is not going to lower the suicide rate. Japan and Europe are, unfortunately, perfect examples.

Monday, September 14, 2009

Does Violent Crime Disproportionately Affect Women?

"a violent world that disproportionately targets women" - Weer'd Beard said this on a comment on another blogger's website and I had to ask myself: "Is violence disproportionately skewed towards women?" Seems like a rather easy question to answer so I went searching.

The Bureau of Justice Statistics compiles this type of information from their crime victimization surveys. On the most basic level, one could say no based on this graph:

Violent crime (murder, rape, robbery, assault) has been committed against males at a higher rate since at least 1973. However, looking at the graph and examining the underlying data, one can see that males have experienced a sharper decline (63%) than females (52%). Reviewing data from the 2006 and 2007 Crime Victimization surveys one finds that the rate between males (22.5) and females (18.9) has narrowed further. So, in the next 5 years we might see that violent crimes are committed against females at a greater rate than males.

So initially, I'll say that I disagree with Weerd, with some stipulations. 1) I'm looking at data from the US. 2) The trend indicates that Weerd will be right in a few years (so he may just be ahead of his time). If I stopped there, this would be an uncharacteristically short blog. So I won't. Perhaps my initial disagreement is wrong.

Based on the violent crime rates, about 2.7 million are committed against men and 2.4 million are committed against women. While not identical, it should be close enough to find any disproportionate amounts. The two impacts that I want to look at are deaths and injuries. So, let me change my original question to "Does violent crime cause a disproportionate number of deaths and injuries to females?" I'll use WISQARS as my source data for the years 2001 - 2006 (reason being that they have deaths recorded through 2006 and their comparable injury information only goes back to 2001). It should be noted that the death information will be more accurate since it is gathered by counting the total number of deaths. Injuries is done using a survey method and extrapolating to the entire population. As usual, my conclusions will come at the end (hence the word conclusion), and I'll be more than happy to tell you if I am wrong. So, in summary to start, based on the BJS chart, for the present time, I think Weer'd is wrong. Let's see who is right?

Violent crime as defined by the government consists of murder, rape, robbery and assault. WISQARS has a dataset for fatal injuries that has a subcategory of homicide. As part of the non-injury dataset, it has subcategories for sexual assault and other assault. I'll use the sexual assault as a rough approximation of rape injuries. The other assault I will use for the robbery and assault category. These categorizations are not perfect, but we rarely get to do a lab experiment when it comes to crime (those pesky criminals don't always cooperate and it is hard to get volunteers to be the victims). I'll then see how the comparative WISQARS rates match up to the BJS rates. A couple of things that I won't be looking at is the psychological cost of these crimes and the monetary cost of these crimes.

To begin I used the homicide and assault categories to gather information on cut/pierce, drowning, fall, fire/burn, firearm, poisoning, struck by/against, suffocation, and motor vehicle. Then I calculated the comparative rate between the two as a percentage (female rate/male rate * 100). If the percentage is greater than 100% than it disproportionately affects females.

To begin here is the graph of homicides:

The first thing that caught my eye was that only suffocation and drowning had any values above 100%. From a logical standpoint this makes sense. Murder by suffocation and drowning are brute force methods. There are no force multipliers. A rope may be used around someone's neck but this does not necessarily multiply the force. Given the fact that the average male has more upper body strength than the average female and that predators (criminals) tend to target the weak, it makes sense that brute force methods would disproportionately affect women. However, as can be seen from the total, homicide statistics are driven by firearm homicides which disproportionately affect men (five times the rate as women). Looking at the BJS rate comparison from 2005 the comparative rate is 26%. This is very similar to what I found from WISQARS.
Now for the assaults (which would be robbery and assault):
Again, the overall shape is similar to the homicide chart (minus drownings, it is hard to get injured from drowning). Vehicular injuries has a couple of years where women are about equally affected (100%) which is curious to see since, there wasn't the a similar comparative rate for homicides. The total is driven by the Struck By/Against category since they account for nearly 10 times the injuries as the next closest (Cut/Pierce). What these two graphs combined tell me is that Weer'd intention with his comment may be the force disparity that women have in unarmed combat. Suffocation is an indicator of this. Going up to my two assumptions in the preceding paragraph, an average male preying on an average female is going to have a strength advantage. A female preying on another female is going to select her prey so that she has a strength advantage. So if this was Weer'd intention, I would have to agree, however the way he worded it originally doesn't easily lend itself to that conclusion. Looking at the BJS comparative value for 2005 it is 62% when combining robbery and assault numbers. Once again this is similar to the numbers I calculated from WISQARS.

And the last graph Sexual Assualt or Rapes:
The first thing that should be obvious is the scale. Rape and sexual assault disproportionately affect women in a big way. That isn't news to anyone I hope. Further, injuries primarily occur in the struck by/against category. This also shouldn't be a suprise. The BJS found that only about 7% of rapists use weapons during their crime. The vast majority are just predators seeking out easy prey that they can use their strength disparity. Looking at the comparative rate for the BJS it is 1400%. This is higher than the values I calculated, but then again, they are surveying all rapes and sexual assaults while WISQARS is only looking at injuries. Still, as far as the order of magnitude goes, they are very similar.
Overall, violent crime rates are driven by assaults. There are 10 times as many assaults as robberies, 4 times as many robberies as rapes and 20 times as many rapes as murders or 800 times as many assaults as murders. Of the four categories of violent crime, women are disproportionately affected by rape. However, the trend of violent crime victims by gender appears to indicate that we may be seeing more of the violent crime targeted to women in the near future. So in conclusion, I still think Weer'd is wrong, for now.
That all being said, I don't think women (or men for that matter) should sit back and pretend crime doesn't happen. On the reverse side, don't paralyze your life because of what is going on in New Orleans or Chicago. Looking at the Crime Victimization reports can tell you a lot of things.
1) Women are 50% more likely than men to be victims to someone they know (family or friend). Lesson: Know your friends and family.
2) 25-34 year olds are half as likely to be victims of violent crime as 12-24 year olds. The rate drops an additional 25% for 35-49 year olds, an additional 33% for 50-64 year olds and finally an additional 80% for those over 65. In other words, a 65 year old has only 5% of the risk of being victim of a violent crime as a 20 year old. Lesson: Relax as you get older.
3) Never married and divorced people are 3 times as likely to be victims of violent crime as married or widowed people. Lesson: Get married and stay married.
4) Urban residents are 50% more likely to experience violent crime than suburban or rural. Lesson: If you can, get out of the city.
Bottom line. Choose first to not be a victim. Take the necessary steps to not make yourself an easy prey.

Friday, September 4, 2009

The Latest Wacky Idea from American Protectionists

American Protectionists have come up with another of their wacky ideas. Putting "Buy American" provisions in the stimulus bill wasn't enough. They forgot to add those provisions to the "Cash for Clunkers" and we find that foreign automakers made off like bandits! (Naturally, I don't care about the foreign automakers making off like bandits, I encourage all companies, foreign and domestic, to make off like bandits if by that we mean selling products to people that they want). Now Gen. Wesley Clark and his cadre are trying to get country of origin labeling on oil.

I first heard of this coming into work today. And I laughed out loud, I thought it was a joke. So searching the news, I find that it isn't a joke, these people are serious. And they don't know what they are talking about either. Having worked in the oil industry I know a thing or two about it.

So let's start with the whole country of origin labeling thing anyway. What does "Made in the USA" mean? Well, it can mean any number of things. It could mean that the final product was assembled in the US (with 100% foreign parts), it could mean that some amount of parts were manufactured in the US, it could mean that the raw materials were from the US, it could mean that the whole shebang was begun and developed in the US (with 100% foreign labor), it could mean that it was actually built in Japan in the city of Usa. Basically, whatever you want it to mean.

Let me say that I am not worried that terrorists are profiting from the gasoline I use, nor do I care that some 10 year old in Vietnam works 12 hours a day at a factory to make my clothes, and I am not worried about the illegal immigrants that pick the vegetables I eat for $10 a day. I only have so much time in my life, I can't save the whole world. So I focus on my family and improving those around me within my means. Maybe when I am independently wealthy I can start to worry about the personal problems of people halfway around the world, but at that time I will try to actually do something about it, not just talk about it and protest in the comfort of my hometown. I wouldn't mind retiring, living in Africa and helping develop village water systems so that people can have clean drinking water. (If I do, you can bet there will be a lot of gasoline or diesel generators spewing out gobs of CO2).

If you are not like me and want to try to save the world, be prepared to have to deal with being a hypocrite. Extreme positions rarely have any wiggle room. Just accept the fact that the coffee you drink is harvested with slave labor, tyrannical dictators skim the money from oil companies for their personal use, and money spent on foreign (and domestic products) is going to go buy drugs, booze, women, and guns for some less than savory people.

So now that you know I have no problem with foreign products, let me talk about labeling the country of origin of oil. What exactly are we labeling? Are we labeling the gasoline itself? Well, gasoline isn't exactly a single product. Besides being a liquid, it is a blend of several liquids. And once those liquids are dumped in a tank or piped through a pipeline, it all gets mixed together.

A Primer on Gasoline
Let's look at the service station where you get your gas. A typical small service station may have three or four 2,000 - 5,000 gallon underground tanks (one for each grade). These probably get filled up once a week when the tank is 1/3 - 1/2 full. They buy their gasoline from a wholesaler. The wholesaler has the gasoline at a transfer station. There are several 250,000 gallon tanks. Several gas companies (BP, Shell, Conoco, etc) may use the same transfer station (it is more cost effective than having everyone build their own - so yes, the transfer station may be run by Shell, but you will see BP tankers pulling up to get their gas). Pipelines run to the transfer stations carrying gasoline from whatever refinery it was made in, or port where it was imported. The gasoline is stored in the big containers. It is all mixed together, because it is all the same thing. The basic content of gasoline is regulated by the government (how much ethanol, how many octane, etc).

So why all the commercials about one companies gas being better than the other? Well, that all has to do with additives. Besides the big tanks with straight gasoline, there are also a bunch of little tanks with each gas companies proprietary additives. So when a truck pulls up to load up 2,000 gallons of Super X gasoline, 1999 gallons of gasoline are pumped in and 1 gallon of Super X additives are mixed with it. This is actually a very efficient process, and allows companies who don't refine gasoline, to still market their own special blend!

So, let's take a step backwards to the refinery. Oil refining is a process where a relatively useless raw material (crude oil) is turned into useful end products. Here is a graphic of what comes from a barrel of oil:

More than 3/4 of each barrel of oil gets turned into fuel of some sort. In the US, we have built our transportation fleet around gasoline (primarily because our initial supply of oil in the US from Texas and Oklahoma was well suited to the chemical process that produces lots of gasoline). Our refining capacity is not enough to supply our demand for gasoline so we import a lot from Europe. Import gasoline. Europe has built their transportation fleet around diesel fuel (primarily because their initial supply of oil from the North Sea was well suited to a chemical process that made equal amounts of diesel and gasoline - they sell the gasoline to the US).

The major factor in the flow of oil is proximity (it costs money to move oil long distances). So at times, we export oil (yes, I said export - the US produces about 5 million barrels a day and export about 1.5 million barrels of it, almost 1/3 of the oil the US produces is EXPORTED - and I am perfectly fine with that) from Alaska to Japan or Korea, because it is more cost efficient to do that and import oil from Mexico or Venezuela (corrupt dictators notwithstanding). when it gets to the refinery, it goes into a big tank (sort of like a transfer station). And it all gets mixed together (Louisiana crude, California crude, Texas crude, North Sea, Saudi, etc.) if it is roughly the same type of oil (light, heavy, sweet, sour, etc. - crude oil is just like cream in some respects). The refinery draws from these feedstocks as they work their magic and presto out comes gasoline and other products.

So we all know that oil comes from evil countries that have no rights, right? Yeah, the top 15 countries that we import oil from include Mexico (backwards I'll give you, but not evil), Columbia (see Mexico), Brazil, United Kingdom, Norway, and Ecuador. If we include all Petroleum imports the Virgin Islands makes the top 15 list as well. Oh, wait, I forgot the number one country that we import from, the evil terrorist hording giant of ... Canada. Wait a minute, Canada? The ones that end their sentences with "eh" and play hockey year round. That Canada? Well, we must barely import more oil from them than the 2nd place evil country Venezuela right? Wrong. We import about 2 million barrels a day from Canada. Venezuela only sells us 1 million barrels a day. In fact of the non-evil countries I mentioned above they account for 40% of our oil imports.

So what about the evil countries? Well, I didn't make a judgement on Nigeria, Algeria, Kuwait, and Angola. They account for another 16% of our imports. Then there is Iraq (which I think is our friend), 4% and Saudi Arabia (just because terrorists come from the country does not mean the country is bad), 9%. Of the top 15 importers, only Venezuela (whose leader actually has spoken about the evil Americans) at 10% and Russia (who keeps on flipping as to whether they want to be our friend) at 3%. So this whole labeling thing boils down to 13% of the oil we import (which is only about 8-9% of the actual oil we use). Got that, 8-9%.

Now that we have a general idea of how everything gets mixed together in one great big soup, how are we to accomplish labeling. I can think of a few ways:

1) We have separate supply streams for foreign and domestic oil. This would necessitate a large expenditure of capital for new tanks, refineries, pipelines, etc. After all we don't want to soil our oil with any of that foreign stuff.

2) We have signs at the pump that change on a regular basis based on the most recent shipment of fuel. The sign would list where the gasoline came from, what feedstocks were used, etc. etc. etc. When you realize that there is no gas in your town that you can buy in good conscience, maybe you will come to your senses and continue to support terrorists and tin pot dictators.

3) Just have a general sign on each pump of where the gasoline came from on average, updated on a yearly basis. This is a scaled down version of #2, hopefully it would assauge the guilt of most of the people that are worried about buying foreign oil. They would be able to buy gas at one gas station in their state.

Now, lets look at some of the logistical problems that might pop up. I mentioned before about the "Made in the USA" label. If the gas is refined in the US, is it "Made in the USA"? If it is refined in Europe with US oil and re-imported is it "Made in the USA"? If foreign gasoline is blended with US gasoline is it "Made in the USA"? What percentage is needed? 50%? 30%? 10%? Does the ethanol or other fuel additives count towards this percentage? What about oil from Saudi Arabia that is pumped with American Made machinery, onloaded to an American flagged ship and transported to the USA?

How about this dilemma, what if for some reason we decided to buy oil only from friendly countries. This would mean that our supply of oil was limited. Best case moneywise for us is that friendly countries stopped selling oil to others and only sold to the USA. In which case those other countries would be faced with the decision to a) buy oil from the "evil" countries or b) have their economy do a nose dive which has always worked out for people's well being. Right.

Or on the other hand, since we have artificially limited our supply (by not buying from whoever has oil to sell), the price of oil to us will go up (since now the people supplying our oil know there is no where else for us to turn). That $140 oil did a good job in 2008 of keeping the economy and jobs roaring, didn't it. So in a way, we are captives to the "evil" countries. But then again, they are captives to us. Who else is going to buy the 10 million barrels we import? There isn't the demand for it. Which means, while they hold our gas spigot, we hold their purse strings. So it is in both of our best interests to just play nice.

I will tell you a solution that I can get behind. Have the US government copyright/patent/trademark the "Made in the USA" label. Then rather than worry about where a product was made, just charge a royalty for each product that contains the label. Those who are socially conscious to the point of wanting to engage in isolationism, can buy their Coca Cola with the "Made in the USA" label for $2.50. I'll pick up the case right next to it that doesn't have the label for $2.25. The fact that they were bottled in the same place less than 20 minutes apart is irrelevant. The "Made in the USA" label already is just a salve to help some not feel guilty about supporting "evil". The US government isn't making any money on it though, and I could get behind that proposal that would change that.

And to top it all off, if you believe we are so righteous because we don't import oil from super "evil" Iran or Libya, try this out. Europe does, a lot of it. And remember what I mentioned about them exporting the gasoline that they don't need because they rely on diesel? That's right it comes in to the good ol' USA and you pump it into your Toyota hybrid every time you go to the pump. Even when we embargo countries we still end up using their products.

Not to beat a dead horse, but look at that graphic again. A little more than 7% of the oil we use goes to "Other Uses." What are those? Things like plastics, petroleum jelly, and tar. So while you may be buying your organically raised milk that is certified from Vermont, it is coming to you in packaging that was made from "evil" oil. Every time you put some lotion on, you are donating a few tenths of a cent to the terrorists. Simply driving your car (even if it is all electric or runs on 100% ethanol) helps support Hugo Chavez because the heavy oil they have in Venezuela results in a higher amount of tar than light oil from Texas or Saudi Arabia. All asphalt is is tar and gravel. I can see the signs now, "This road was paved courtesy of the communist Hugo Chavez, by driving on it you are directly supporting his regime."

Tuesday, September 1, 2009

Grilling: Gas vs. Charcoal

No, I am not writing this to further the debate of which is better (Clearly charcoal is). Sorry, this has to do with the general population not understanding how to use basic statistics, and going ahead anyway to use them to try to prove their point.

At work, our monthly safety bulletin was about grilling. Rather appropriate for the summer. The first error made was in the title "The Backyard BBQ." BBQ is a style of cooking and using an outdoor grill does not make it BBQ. It's called grilling - and can be just as tasty as BBQ I might add. But I digress, the title had nothing to do with the statistics. The following phrase however did:

"81% of the grills were fueled by propane/gas and 16% used charcoal or other solid fuel. Although gas grills are only used roughly 1.5 times as often as charcoal grills, they were involved in five times as many fires."

The emphasis was in the handout, I didn't add it. When this was read, I did a double take and had to look at the sheet to see if it really said that. It did. The point they are trying to get across is that even though gas grills are more popular, they are the cause of a disporportionate number of the fires. So let's look at the statements.

First, 81% of grills are fueled by propane/gas and 16% used charcoal or other solid fuel. I am assuming that the remaining 3% or grills are liquid fuels (although, I have never actually seen one of those, unless you consider a Coleman stove a grill). I have no objection to this, it makes perfect sense. Go down to the hardware store and the vast majority of grills are gas.

Next, gas grills are used 1.5 times as often as charcoal grills. OK, this can be taken one of two ways. A) (an absolute view) For every 2 uses of any charcoal grill, any gas grill is used 3 times or B) (a relative view) For every two times the average charcoal grill owner grills, the average gas griller grills three times. They may seem the same, and if there were equal numbers of gas and charcoal grills then they would be. But there are not.

So, let us do a little math. Assume for a moment there are 81 gas grills in the US and 16 charcoal grills in the US. We know how many grills there are so we want to calculate total uses. Using the absolute view (A) above, if every charcoal grill is used twice in one year, they account for 32 total uses. This would mean the gas grills account for 48 total uses (1.5 time 32). In other words, at least 33 of the gas grills were never fired up even once. Another way of looking at it, is that 16% of the grills (charcoal) accounted for 40% (32) of the total uses (32+48=80). Does that make sense?

No, it is like saying that people with charcoal grills are 3.8 times ((32/16)/(48/81)=3.78) as likely to grill as people with gas grills. Having owned both gas grills and charcoal grills, I know this can't be true. While I love the taste of charcoal flavored burgers, nothing beats the ease and convenience of turning the knob, pushing the button, and pop you have your flame. I grill more often with gas than I do with charcoal, because of the ease of use.

So let us look at the relative case (B) to see if it makes sense. Since each of these is an average griller, the percent ownership is irrelavant. So it is simply stating that if you own a gas grill you are 1.5 times as likely as a charcoal griller to use your grill. This is the point of what is being said. I hope you are still following along.

Now the last part, gas grills are responsible for five times the number of fires. This is said as the ominous warning. But is it really? Let us look at our first set of numbers, 81% vs 16%. Turns out there are approximately 5 times as many gas grills as charcoal grills. This statement can also be taken in an absolute or relative manner so let us examine both for the common sense test.

Absolute. Of the total number of fires, five times as many are caused by the gas grills. We can assume that a fire isn't going to happen unless the grill is used, so each use should count as a potential. We already know from above that 81 grills x 3 uses + 16 grills x 2 uses = 275 total uses. If we assume that 13.3% result in fires (no where near this high in real life but this is just for comparison purposes) then the 275 uses will result in 36 fires. Of that 36, 6 were from charcoal grills and 30 (5*6) were from gas grills. Or a rate of 0.1875 per use for charcoal and .1234 per use for gas. This would indicate that while gas is 5x more prevalent than charcoal, it is actually 51% less likely (.1875/.1234-1=0.51) to cause a fire than charcoal. Hence, no need for the ominous warning.

Relative. If 3% of charcoal uses cause a fire, then 15% (3%*5) of gas uses cause a fire. So, for 32 uses of charcoal grills, there would be 1 fire. For the 243 uses of gas grills there would be 36 fires. Now does this make sense, no not really. There isn't a mechanism that would make gas grills more fire prone than charcoal grills. Granted, if you leave the gas on for a while before lighting it, you could have a nice fireball. However, this pales in comparison to the safety hazard of squirting lighter fluid on your already lit coals. I'll admit, I like to do this! So the relative case to me seems like bunk.

Turns out, the NFPA has these statistics on their website. Of the 7900 fires, 6400 are from gas grills (so I assume that 1500 are from charcoal grills). This confirms my analysis that the relative case is not correct. However, there are still some problems with these numbers. 6400/1500 = 4.3 not 5 times. So this makes the absolute case even more peachy. Even though 4.3 times as many fires occur from gas grills as charcoal grills, since gas grills are 5 times as prevalent as charcoal grills and used 1.5 times as often, they are actually 57% (4.3/5/1.5=0.57) less likely to cause a fire (hence they are much safer).

So really, what the NFPA (and my work) should be saying is that charcoal grills are fire magnets! And without changing any other practice (like not grilling indoors), if we switched the 16% of charcoal grills to gas grills, we would decrease the number of fires by 11% (57%*1500/7900=0.108).

Now, if this doesn't bore you, I don't know what will. I find it rather exciting!