# Domino Risk Assessment and Management

Domino is a game in which players place domino tiles edge to edge on a table so that the open ends of the tiles match each other or form a specified total. In some games, the player scoring the most points wins. Dominoes were first recorded in use in Italy and France around the mid-18th century.

The term domino may also refer to a set of rules for a particular game or the process of playing it. It can also be used to describe a chain of events or an uncontrolled escalation of a situation. In the context of disaster risk assessment and management, the term domino effect refers to an unwanted event that “propagates” into one or more larger-scale events, often with catastrophic consequences.

Using a simple, but effective, methodology, this article develops an approach for assessing the risk of domino effects. This approach is based on the use of Event Tree Analysis (EtA) and probabilistic modeling. The approach allows for the evaluation of different scenarios and a comparison of the probability of occurrence of a domino effect with respect to other parameters, such as location and severity.

The domino game consists of a base, called the stock, and the tiles (also known as bones, cards, men, or pieces) that make up the rest of the set. Each domino features a square face that is divided into two matching sides, or ends. Each end has a value that may be any number from six pips up to no pips. This value is referred to as its rank or weight, and a tile that has more pips is heavier than a similar tile with fewer pips.

After the dominos have been shuffled, the players draw a domino from the stock and the player who draws the heaviest tile makes the first play. In some games, a tie is broken by drawing new dominoes from the stock. The player who makes the first play sets his or her tile, and then follows the rules of the particular game being played to determine what else should be done with the tiles in the hand.

Many domino games involve a line of play, with each player placing a tile in the line until it is complete. A single tile can be placed to the left or right of a double, but must touch both the double and the next tile in the line. Whether or not the double is a spinner, it must be played perpendicular to the domino with which it was joined.

Besides the basic rules that pertain to most domino games shown on this website, there are many other ways to play the game and a great deal of variation in the way a hand or game is scored. For example, a rule that is common to several games requires that the winning player count the pips of the dominoes remaining in his or her hand at the end of a hand or game, and then adds that number to his or her score.