# How Huff's Equal Probability Trade Areas (Business Analyst) works

The Huff's Equal Probability Trade Areas tool generates areas of competitive advantage boundaries between stores weighted on one or more variables. These weights can be calculated based on the results of a Huff Model.

The basic premise of the Huff's Equal Probability Trade Areas tool is similar to the Thiessen Polygon tool. With the Thiessen Polygon tool, a line is drawn halfway between two competing centers and provides a basic approach to drawing boundaries between stores. In contrast, the Huff's Equal Probability Trade Areas tool takes it a step further. This approach utilizes the basic principles of the Huff Model to determine the sphere of influence of each store relative to each other. Factors such as attractiveness and the distance decay coefficient determine how these boundaries are drawn.

There are two options to generate these boundaries:

- Manual—Allows you to enter your distance decay coefficient and attractiveness values based on the data contained in your store data.
- Huff Calibrated Model—Allows you to import a Huff calibration generated using the Business Analyst Modeling tools.