Design & Audit Tips, Part I   

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I. Getting Started

Before you begin building a worksheet, spend some time thinking about the data you're going to model and the problem you want to solve. Try to identify the inputs and outputs and the relationships among the data.

Inputs
Outputs
Relationships

 

Inputs

Known Values

Any known values or given data. These are quantities you don't control.Do you need any additional data to build the model?

Decision Variables

Quantities you control and can manipulate to optimize your model's solution. In some cases, decision variable values may be efficiently optimized by using tools like Excel's Solver.

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Outputs

The Object

What you're trying to solve, find, show, or optimize: the "bottom line".

Any Constraints

Limits to inputs or outputs, tradeoffs, conditions you must meet. Examples of constraints are budgetary limitations or limits to available resources.

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Relationships

Relationships Between Variables

Relationships between the known values and decision variables, expressed in formulas. Not all the relationships may at first be clear, especially in a complex problem. They may become more clear as you work through the development of your model.

A Pattern

Whether or not your problem fits into a "family" of problems for which you might employ a generic model structure. For example, problems dealing with resource allocation or scheduling have traditional formats you might want to adopt for your model.

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