Think Twice

You have probably heard the expression "think twice." It is a reminder to be careful about assuming that your first conclusion is correct. Carpenters have a similar saying: "measure twice, cut once," which is a habit that prevents a lot of mistakes. Thinking twice does the the same thing in many areas - it prevents errors. Getting familiar with some of the common "thinking errors" also helps you avoid them, so here is a look at one that trips up a lot of people.

Straight-Line Projections? Think Twice

When he first visited the ocean, a scientist noticed that the water level getting higher. He carefully measured it for a few hours, then noted that every hour it was going up a foot. With his pen and paper, he quickly calculated that the ocean would be 700 feet higher in less than a month, drowning most of the major cities on Earth. In a year only the highest mountains would be above sea level.

He ran off to sound the alarm and show his calculations to others. Of course, they knew the ocean better than him. It came up every day the people explained, but then it went down again later. This was the tide, they explained, something he somehow hadn't learned.

Do you think this silly story has no relevance to real science and scientists, or your own errors? Think twice! This thinking error can be found all over. For example, a cooling trend in the 1970s had some scientists proclaiming that Florida would be too cold to grow oranges by the 1980s. Todays more extreme projections of global warming are probably based on the same error (of course they could be wrong in either direction).

Here's a true story: In 1975, my very serious science teacher showed us a very serious film which proved oil supplies would be depleted in fifteen years. It is true that there was (and is) just so much oil on the planet. It was also true that our use of it was growing. The math showed we would clearly run out soon.

But we didn't run out in 1990, nor in the seventeen years since then, nor are we likely to in the next seventeen years. "Scientific" projections like these often rely too much on math and those lines on a graph. When other factors are considered, they are often just used in ways that confirm the theory that has already been established. The thinkers involved may be very intelligent, but their thinking-error is in assuming complex interactions can be reduced to simple formulas which can then be used to make accurate predictions.

Let's look again at the example, and what was ignored. When the price of oil rises, producers try to find more oil - a factor apparently ignored in the projections. If these scientists had thought twice, they may have easily stumbled upon the idea that maybe we hadn't yet found all the oil out there - and that high prices would make people want to find more.

Higher prices usually reduces demand as well. It's not hard to imagine that people would use less gas if dwindling supplies caused the price to go from 50 cents-per-gallon to $4 or even $15. They apparently ignored this normal economic reality as well.

High prices increase demand for alternative energy sources too. It's reasonable to assume that many alternatives look attractive when oil prices are ten times as high, right? And this means there will be substitutes for oil long before it runs out. This normal economic reaction was ignored. That "scientific" film assumed that without government action we would just keep using oil in the same way until one week it was gone. In hindsight, it seems like the "science" of a child's mind.

Whether economic, biological, psychological, political, or ecological, many systems are self-correcting to an extent. They have trends which look like they'll continue to head in a given direction, but other factors prevent this from continuing. This isn't to say that things always return to some norm, or in a statistician's terms, "revert to the mean." But in most areas where we try to predict the future, the interactions of the various factors are complex enough that we aren't likely to have much success.

Wouldn't it be nice if predicting the future was as simple as collecting data, making a graph or two, and assuming things will continue in the same direction? A nice thought, perhaps, but life is more complicated than straight-line projections can account for. Collecting data and trying to make sense of it is important, but before you think you see where the data is leading, take a look at anything which might affect those predictions. Think twice.

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