Before training her new staff on implementing discrete trial training (DTT) with clients, Denise first gives the staff written instructions and takes data on their implementation of DTT during role play sessions. Next, Denise uses behavior skills training (BST) to teach her staff one at a time and takes data on their implementation of DTT with actual clients in order to demonstrate that BST was effective in improving staff performance. In this scenario, Denise is specifically adhering to which characteristic of the scientist-practitioner model? Taking an empirical scientific worldview Demonstrating an analytic approach to problems Implementing literature review skills Using a fundamental research design