It uses logic to express knowledge, and it uses inference to manipulate knowledge. The Knowledge Base, in order to eliminate human errors, performs calculations, carries information forward to appropriate fields, and sums total amounts automatically. Also, since tax forms contain so many duplicate values, Prolog provided the best means to handle the redundant values on all the forms. Due to Prolog, the user has no need to enter the same information more than once. The workflow for CyberTax is simple due to Prolog handling most of the logic for each form.
Users simply enter their tax information by tabbing to and entering data into simple edit boxes.
After the data is entered, it is passed to the built-in Knowledge Base which analyzes the information. This approach provides a quick and effective means to perform all of the related computations in all of the supported tax forms. The method also works well for getting estimated tax results. For example, a user could enter guess values into the edit boxes. The program would then handle the computations, thus allowing a user to get a feel for what the tax situation would be under certain circumstances.