Group N0. 8 Viraj Modi 2013053 The Awesome Power of Twenty Questions

It's a common classroom game for grade-schoolers and yet it contains a profoundly powerful problem solving strategy which can be used to de-bug software, troubleshoot equipment and solve problems in business and industry. In the game one child picks an object and everyone else has 20 questions to identify it. At first the children guess specific items but they soon realize they need to eliminate entire categories or risk using up their 20 questions before finding the answer. 

The principles of twenty questions are frequently used in the business world to conduct computerized searches of massive data bases. These are called a binary searches and are one of the fastest search methods available. To conduct binary searches, data must be sorted in order or alphabetized. The computer determines which half of the list contains the item. The half containing the item is divided in half again and the process repeated until the item is found or the list can no longer be divided. 

Just how powerful is 20 questions? The correct alternative can be identified from among 2²⁰ or 1,048,576 different alternatives assuming that a "no" has the same weight as a "yes" answer. In other words, either answer eliminates half the alternatives on each question. For example, consider the question, "is the object in this half of the room." A yes or no question will generally eliminate half of the objects in the room.

The principles of twenty questions can be used in any trouble shooting or problem solving situation where the problem is associated with a single element of a complex system. Problem solvers should avoid focusing on the cause and instead ask which elements of the system can be eliminated as causes. Data collection and experiments should attempt to eliminate half of the alternatives with each effort. 

Element should only be eliminated based on data. No element should be omitted because it is too new, traditional, high tech or expensive to be the problem.

Typical data collection techniques often will not eliminate elements. For example a full gas gauge would not eliminate the fuel system as a reason why a car won't start. The fuel pump might be broken. A great deal of creativity is often needed in collecting data. However, low tech methods such as looking at the equipment should not be ignored even when no one knows what to look for. After all Columbus discovered America by looking for India.

When most of the elements in a system have been eliminated its time to develop a hypothesis about what caused the problem. Using this hypothesis, list possible causes and test them until a solution is found. The chances of success are much higher when working with a limited number of elements rather than the entire system