97 There are several contexts in which randomization in research design is not possible. Researchers may be interested in the effects of large-scale events or policy initiatives, or of complex causal processes that cannot be replicated. Threats to external validity in randomized experiments will lead to greater dividends for some research questions in a quasi-experimental design. Quasi-experime...

This paper compares the advantages and disadvantages o f the "pre-planned" and "postplanned" approaches to evaluating program effectiveness. These evaluative approaches are compared along a number o f dimensions which include: (a) Reliability o f data and the cost o f collecting it; (b) Internal validity; (c) External validity; (d) Evaluation obtrusiveness and threat; and (e) Program goal displ...

BACKGROUND Interest in evaluating and improving children's diets in afterschool settings has grown, necessitating the development of feasible yet valid measures for capturing children's intake in such settings. OBJECTIVE The purpose of this study was to test the criterion validity and cost of three unobtrusive visual estimation methods compared with a plate-weighing method: direct onsite obse...

Objectives: Different treatment approaches have been introduced for children with Speech Sound Disorders (SSD). Minimal pair intervention, Metaphon therapy, and parents and children together approach as linguistically-based approaches are routinely utilized in this population and both of them shared minimal pairs as a common component. The purpose of the current study was to develop and investi...