When one looks at transcripts of people answering questions or carrying on dialogues about everyday matters, their comments are filled with plausible inferences -- inferences that are not certain, but that make sense. Often, in forming these inferences, generalizations are made that are equally uncertain, but are nevertheless useful as a guide to their reasoning. This paper describes some extensions to our earlier description of a core theory of plausible reasoning (Collins and Michalski, 1989), based in large part on a recent protocol study. The primary focus is on the inductive inference patterns people use to form plausible generalizations, weakly held beliefs based on few examples. W e also show how the model was extended to deal with plausible inferences involving continuous quantities and inequalities.

The notion of cases arises in various guises in a number of areas of research within Cognitive Science. Recent theories of situated cognition, for example, have argued that learning occurs most felicitously in circumstances that most closely resemble those of eventual use (Brown, Collins, & Duguid, 1989; Norman, 1993). Furthermore, research in analogical problem-solving has shown that transfer is improved when the similarity between training problems and target problems is increased (Gick & Holyoak, 1980). Both positions, therefore, support the argument that instruction based on cases is more likely to be usefully applied in practice than instruction based strictly on abstracted principles. Others have gone further to argue that learning through exposure to real cases is not only beneficial, but essential for attaining expertise. For example, Dreyfus has asserted (Dreyfus & Dreyfus 1986) that advanced stages of expertise can only be achieved through practice with a large number of cases. Moreover, advocates of Case-Based Reasoning (Kolodner, 1994) have argued that the process of acquiring expertise is really one of accumulating experience with a succession of real cases and properly indexing these experiences for later retrieved. The purpose of this symposium will be to determine to what degree these views are compatible and to what degree they diverge. The presenters will endeavor to address the following questions from their own disciplinary perspectives: What is a case? How is it represented in memory? How are appropriate cases retrieved for later use? Does expertise consist (strictly) in the acquisition of a collection of past solved problems? What role should the study of cases play in the acquisition of expertise? Should they precede or follow the study of abstracted principles?

Substantial heterogeneity in practice patterns around the world has resulted in wide variations in the quality and type of dialysis care delivered. This is particularly so in countries without universal standards of care and governmental (or other organizational) oversight. Most high-income countries have developed such oversight based on documentation of adherence to standardized, evidence-based guidelines. Many low- and lower-middle-income countries have no or only limited organized oversight systems to ensure that care is safe and effective. The implementation and oversight of basic standards of care requires sufficient infrastructure and appropriate workforce and financial resources to support the basic levels of care and safety practices. It is important to understand how these standards then can be reasonably adapted and applied in low- and lower-middle-income countries.

Substantial heterogeneity in practice patterns around the world has resulted in wide variations in the quality and type of dialysis care delivered. This is particularly so in countries without universal standards of care and governmental (or other organizational) oversight. Most high-income countries have developed such oversight based on documentation of adherence to standardized, evidence-based guidelines. Many low- and lower-middle-income countries have no or only limited organized oversight systems to ensure that care is safe and effective. The implementation and oversight of basic standards of care requires sufficient infrastructure and appropriate workforce and financial resources to support the basic levels of care and safety practices. It is important to understand how these standards then can be reasonably adapted and applied in low- and lower-middle-income countries.