The principles/steps/symbols in building influence charts

The principles/steps/symbols in building influence charts :
An influence chart is something of a free form visual aid that helps us conceptualize a model. Similar to a flow chart but not as step by step – does not delve into the minutia of each element of a step by step process – if A than B; if B is true go to C if not repeat A et… A flow chart can be based on Boolean logic. An influence chart is a high level thought flow, about areas of concern, which should be given treatment in some way for a given outcome to be achieved. Each outcome leads to another until some final result is achieved. While the outcome of a flowchart is known; it is constructed in order from beginning to end. In contrast; an influence chart starts at the end (objective) and works outward. This is achieved by decomposing the objective into variables needed to obtain the objective and then further decomposing each variable as needed to arrive at the component variables for the parent variable. Each variable might have fixed input parameters and random input parameters. As an example the variable “profit” might have a sub-variable of “expenses”; “expenses” might have fixed input parameters such as “cost of goods”, “depreciation”, and “interest”. A variable could also be some function of the manufacturing process with sub variables such as temperature and humidity. The symbols used are up to the creator or organization - the important factor is that they are consistent thorough out the chart.