Influence Chart

An influence chart is composed with the following symbols:

Outcome- the outcome represents the determining factor or effectiveness of the model. It is by observing the outcome that the model is rated as a success or the need for reconstruction. It is represented by a hexagon.

Variable- Variables are individual elements that combine to create an outcome or another variable in an influence chart. Variables are represented by a circle.

Fixed Input Parameter- Variables that are non-changeable are identified as a fixed input parameter. They are represented by a triangle.

Random Input Variable- These variables cannot be calculated or guessed and have uncertain values. They are represented by double circles.

Decision- The decision is the variable that will provide the solution to the problem. It is represented by a square.

An influence chart is guided by principles depicting the use of each symbol. Approaching an influence chart begins with finding the outcome which is the factor that will indicate the effectiveness of the model. For example if a company will monitor sales to rate the effectiveness of a model then sales is the outcome. The next principle involves breaking down the outcome into variables. After each variable is determined this set of variables should also be broken down. Inputs are marked through this process as well as decisions as they are discovered. Inputs are wither fixed or random. To illustrate the difference consider a company trying sell a product to the highest offer. The offer is a random variable because it is not known.  No variables are repeated throughout constructing the chart. Lastly the symbols used must be applied consistently and uniformly. This means that each factor (outcome, variables, fixed variables, etc.) in the chart should have a specific symbol.