Nowadays, technology advances have been growing exponentially, creating many branches of possibilities for new products and ways to improve the ones that are already on the market. These new possibilities have been used in the automotive industry to increase efficiency, quality, robustness of their products and also to introduce several functionalities that were not possible before. As result, project complexity is also exponentially increasing. On this context, several tools, techniques and processes have been developed and used to guarantee the quality and robustness of their products, while minimizing development time in order to stay competitive at the market. Considering this context, the use of Hardware In The Loop systems (HIL) is increasing, due to its flexibility, reliability and representativeness that have been verified over time for verification and validation activities using Electronic Control Modules. However, usually the HIL setup quality evaluation is measured indirectly (for example model accuracy) or even just qualitatively. It is hard to define how representative is the HIL setup when compared with the final application. This representativeness depends on several aspects of the HIL, such as model accuracy, precision, signal reliability, technical specification of the elements that composes HIL equipment, as well as the nature of the tests that needs to be done. Thus, this paper presents some main concepts related to the representativeness and use them as a base to show a methodology to estimate the representativeness of a HIL application setup for validation and verification purposes. To illustrate this methodology, some test examples were used on powertrain HIL system.