What is the Dice Game or Match-Bowl Experiment?
The Goal Summary | TOC Main Page
Note by James R. Martin
At lunch on the hike Alex develops an experiment with bowls and matches to model a balanced plant. Bowls represent work stations, matches represent product inventory and one die (from a pair of dice) is used to simulate the statistical fluctuations (variation) in performance at each work station or operation. The bowls are set up as a production line representing dependent events where each operation has the same capacity, i.e., six products per day with a range of variation from one to six.
Each player (scout) rolls the die to determine how many matches to place in his bowl. This represents one day's production for that operation. For example, if the first player rolls a six, then he places six matches in his bowl. If the next player rolls a four, he can only move four matches from the first bowl to his bowl. Each operation is dependent on the upstream operation for input. If the next scout rolls a five, he can only move four to his bowl because there are only four available in the previous bowl (upstream operation) in the process. The first scout to roll the four became the bottleneck operation. If another player down stream rolls less than a four, then he becomes the bottleneck.
The scouts each roll the die several times in sequence to represent several days production and each time the bottleneck nearly always appears at a different operation or scout. The point of this game, or demonstration is to show that where each operation in a sequence of dependent events has the same amount of capacity (a balanced plant), the variation and dependent events will cause the bottleneck to move from operation to operation, i.e., floating bottlenecks occur. Managers will not know where the bottleneck will show up next and will not be able to manage the system.