This study applies the Technology Acceptance Model (TAM) to determine whether future users of an information system are able to accurately differentiate between "good" and "bad" prototypes. TAM has previously been used on completed systems. However, by the time a system is completed, development resources have already been expended and changes to the system are difficult and expensive. It would be beneficial to be able to assess intent to use the completed system early in the development cycle. A developer would determine probable system usage by having potential users of the system work with the prototype, then complete the TAM instrument.Results of our study indicate that TAM can be used as a simple, low-cost determinant of a "bad" prototype, permitting improvements to be made continuously throughout the development cycle.