Abstract: A method of determining effectiveness of television and on-line marketing communications is disclosed. A method for determining when transference occurs between different marketing vehicles is also disclosed. The method uses a modular system for determining effectiveness of marketing communications which provides an efficient and timely process for measuring the effectiveness of marketing activities. The system is modular so that certain functions may be selectively added based upon the type of marketing communications for which return on investment is to be tracked. Additionally, certain functions may be added to the system based upon the type of information and the level of detail of the information that the system provides regarding the effectiveness of marketing activities.