# How good are you at estimating?

Strategic decision-making often requires you to estimate current and future quantities. Here’s a quiz to see how good you are at it.

For each quantity below (2009 data unless noted otherwise), make your best guess. Don’t try to find the answers, just guess.

1. World camel population
2. Annual consumption of popped popcorn in the US (quarts)
3. GNP of Belgium (\$M)
4. Number of cats in the US
5. Population of Romania, 2007
6. Amount of dog feces produced each day in the UK (tons)
7. 2007 US corn production (thousand bushels)
8. Value of all the tea in China (annual production) (\$)
9. Total amount of gold ever refined (kg)
10. Acres planted in cotton in the US, 2006 (thousands)

Now how confident are you in your answer? Give a high and a low guess so that you are 90% certain that the true answer lies between high and low.

Don’t check the answers below until you’ve done this!

Here are the answers. Give yourself a point for any question where the answer was between your high and low.

1          World camel population         18,871,000

2          Annual consumption of popped popcorn in the US (quarts)            16 billion

3          GNP of Belgium (\$M)            \$264,000

4          Number of cats in the US       76,430,000

5          Population of Romania, 2007 22,276,056

6          Amount of dog feces produced each day in the UK (tons)    992

7          2007 US corn production (thousand bushels)            13,073,893

8          Value of all the tea in China (annual production) (\$)  \$1,590,653,400

9          Total amount of gold ever refined (kg)           154,400,000

10        Acres planted in cotton in the US, 2006 (thousands)            15,274

How did you do? If you really were 90% certain, you’d expect to get a score of about 9.

I’ve never had anybody get that much. Most people will score maybe 1 or 2. Why is that? It’s the overconfidence bias. We tend to think we know more than we really do. We tend to lock into an answer and then have trouble thinking much beyond it. This is a natural human bias that stifles our imaginations and leaves us unprepared for inevitable changes.

You probably didn’t know the answers to any of these questions. Admit it! Give yourself a wide latitude for the possibilities. Have you ever been caught by the overconfidence bias, or seen others get caught up in it?