Financial Support. Although several RTI models have been implemented in various parts of the United States, there is very little information available about the comparative costs of RTI with more traditional service delivery models. However, the changing personnel needs, increased resource requirements, and added professional development activities typical of initial implementation of an RTI model all suggest there will be increased costs, at least in the short term. Designated instructional services, such as speech and language, occupational therapy, educational therapy, and psychological services will also need continued funding.