Decision table

Decision tables are one of the basic techniques used in solving problems and decision making. Using decision table one can in a concise way specify, under predetermined conditions, what actions should be taken. Decision table is a specific way of describing a set of related decision rules.

Source: (S. Wrycza, 1996, pp. 121)
Example decision table to determine the size of discounts to customers. Source: (T.Witkowski 2000, p 284)

Structure of decision table

Each table is divided into four main fields (S. Wrycza 1996, s. 120-121):

  1. Conditions - formulation of the necessary conditions in the process of deciding, the definition of variables affecting the decision process,
  2. Actions - decisions, listing all the possible actions that can be executed on the assumption that specific combination of conditions contained in the first field of the array occurred,
  3. Selection criteria - there are presented all the states of individual conditions, indicators, values, Symbol placed in this field indicates whether the condition has been fulfilled or not (usually used symbols: "1" condition fulfilled, "0" condition is not met, "-" the condition is not significant).
  4. Action selection - contains symbols identifying that particular action should be performed (used symbols "X" - action should be taken, "-" actions should not be taken)


Author: Krzysztof Wozniak