Software Nerd

Monday, February 26, 2007

Immigration: Cutting in front of "the line"

One of the minor arguments against illegal immigrants is that they're cutting ahead of other people who're waiting in line. There are two problems with this argument.

Problem 1 -- Multiple Lines: Today, the US has many different lines for immigrants. Not everyone waits in the same line. For instance, when waiting for a "Green Card" there are many different categories, and each has it's own waiting list.

The three major categories are "Family based" , "Employment based" and "Diversity". That's not just three waiting lists either. There are 25 (yes twenty-five) different waiting lists within the "Family" category. A person is assigned to a list based on two criteria: type of family relationship, and country of origin. When considering country, India, China, Mexico and Philippines each have 5 waiting lists and all other countries together have 5 lists of their own.

Consider an example from the latest visa bulletin. A Malaysian in the "unmarried son queue" has reached the top of the line if he applied for a Green card in 2001 (yes), while a Malaysian in the "brother" category would be at the top of the line if he applied in 1996 (yes, 10 years of waiting). Meanwhile, a Filipino in the "unmarried son queue" has reached the top of the line if he applied for a Green card in 1992 (yes, check the link for yourself), while a Malaysian in the "brother" category would be at the top of the line if he applied in 1984 (I'm not kidding).

The employment categories are much better. Effectively, there are about 9 different lines and the worst one is backed up only to 2001.

Problem 2 -- Wrong Context: There's another, problem with the "breaking the line" argument, one that is a rather good example of the role of context. The principle that it is wrong to cut ahead of a line is a good one. However, it has a particular context. The typical line is a queue for some type of resource (a movie ticket, a celebrity signature, the opportunity to ask a speaker a question, etc.). When a line is used, it's a recognition that the folks in the line have no "natural precedence", so they'll be treated first-come first-served. (An emergency would be an obvious change of context; but, immigration isn't typically an emergency situation.) There is another important aspect of the typical line: breaking the line puts some people at a disadvantage (the people who are ahead of oneself). This is a vital part of the context that makes breaking a line unjust.

Remove that context, create a situation where breaking the line does no harm to anyone, and the rationale for the "don't break the line" principle disappears. This is the situation with immigration. People who cut in front of the line do not take anything that someone else is entitled to. Further, they do not slow down the rate at which the line moves. In fact, they actually speed up the line for all those who would have got into line behind them. If 1000 people in line before me suddenly melt away, that's good for me.

(One can still object that such people are not vetted against felon and terrorist databases, etc. That's fine, I can buy that argument; however, the line-breaking argument is hereby debunked.)


Saturday, February 10, 2007

Global Warming: Why do Scientists disagree?

Most global warming presentations have at least one graph that shows temperature rising recently. "Global mean temperature" is a fuzzy and its significant is unclear. Nevertheless, putting that aside for the moment, this type of global mean appears to have risen ever so slightly over the last 100 years. Since the rise is so tiny (less than a degree) the global warming theorists have to show more, they have to show that these 100 years are anomalous, when one looks back at the history of the earth. So, to support their argument, they need a graph that looks something like this:

If you aren't familiar with the way this argument is made, this short snippet featuring Al Gore is worth looking at. (Don't worry, it's really short.)

The problem that confronts a layman is that some scientists show us graphs like this from their studies while others show us relatively flat graphs.

As a result, some laymen shrug off the anomalous-looking graph as being the product of enviro-scientists with an agenda, while other laymen shrug off the flat-line graphs as being the product of scientists sponsored by the oil-industry. Nothing in either graph tells us why we should believe one over the other. So, most laymen use their personal political evaluations as a way to make judgement (and this is not totally wrong when it comes to a layman), while other laymen simply look for which graphs have the larger number of scientists rooting for it or which one has the agreement of the United Nations. (Aside: To some, the UN approval is additional proof of truth, to others it is additional proof of falsehood; so, we're really back to politics.)

While a layman may not be able to critique the various studies, anyone with a basic education can understand the issues involved. One can understand why the studies would show such varied results. Here is a brief explanation:

Since there is no way to measure temps from years ago, scientists measure things that they think would have been (at least partly) caused by those temperature changes (so-called "proxies"). This is a perfectly valid approach. However, the approach does raise some issues:

  • what exactly is the relationship of the proxy (e.g. distance between two rings) to thing being measured (e.g. temperature). With many proxies, there is scientific debate about the method of going from the proxy meausrement to the inferred measurement. Different scientists want to use different equations
  • how to handle different results from a particular site (e.g. 4 trees where one shows a history different from the others). Taking a mean of all is often not the right approach, because when confronted with the data it may strike you that that tree is different in some other way that was not accounted for before (e.g. it's position and orientation on the site). There are scientific debates on how best to account for these variations and extract the "signal" from this.
  • when trying to combine data across sites, how does one combine it? For instance if there are three ice-core samples in one area and 5 from another about a mile away, should one take a mean of all 8 or should one take the mean for each site and then compute a mean across the two sites? (For some proxies, using different methods has been shown to yield quite different results)
  • the issue above is compounded when one is speaking of data from sites all over the world (as in tree-ring cases). How does one combine the data to really arrive at a global picture, particularly when the data from different hemispheres and from far-away sites in the same hemisphere show vastly different patterns. Is a mean meaningful? Should the statistical technique of "principal component analysis" be used, and if so what should be the different weights assigned to each site?
  • the issues are further compounded when one tries to combine different proxies. For instance the tree-ring proxies tell a different story from the ice-core proxies. So, how to combine them?
The question, then is: what is the nature of the "deniers" objections? It seems clear to me that the popular ones, many of whom are scientists themselves, are not calling for scepticism (as in "we can never know the truth"); rather they are raising questions about methodology.

Those who want to understand the positions of the Global Warming folks, should look at If anyone here wants to understand the nature of the objections, a good site is one called ClimateAudit.Org, that has a mission of auditing scientific studies that claim global-warming is taking place. Nobody who is not a scientist will be able to make a judgement about which formula to use or what weighting will best portray the causal connections. However, it is worthwhile to get a flavor of the types of objections.

There is a single "anti-GW" paper that acts as a good introduction to the objections. It is titled "What is the Hockey Stick debate about?" by Ross McKitrick. I suggest that anyone who is sceptical about Global Warming ought to at least view the brief Al Gore video that was linked to above, and better still view "An Inconvenient Truth". On the other hand, anyone who thinks the "sceptics" are fools, should read McKitrick's essay and also check out the site.

Monday, February 05, 2007

Carbon Offset: An idea for a scam

Here's an idea for a scam.

Many people want to do more "for the environment" and want to do "the right thing", but don't want to give up their SUVs or turn down the heat in winter. So, tell them that they can be good by giving you a certain amount of money for each "enviro-sin", and you will use that money to couteract their sin: e.g. by planting trees, etc.

The Catholic church and other religions have been following this "sin and buy off punishment" model for centuries, so a good scamster knows it's tried and tested.

You (the scammer) can point out that companies are being made to trade carbon emissions, so why shouldn't individuals do the same. You could come up with a name like "carbon offsets", and let people come to your web-site, calculate how much they need to offset to make themselves carbon-neutral, and how much they must pay you for neutralizing their sinfulness.
Damn! Someone beat me to this scam.