Orientation seems to be more from the psychologist perspective than that of philosophers. There is a good list of reference sites for those doing web based research in aid of making cogent arguments. The tools are commercially available, but he also has some simple investigative tools about attitudes and some of his own research freely available on the site. Both his resources section and assessment tools contain valuable information, for example his Holistic Critical Thinking Scoring Rubric is a good place to start thinking about how to assess the essential ability of critical thinking. A website that actually teaches critical thinking with interactive tutorials.
Emphasis is on the fallacy approach.
The site also includes a list of textbooks with some reviews . A good explanation of Matt Lipman s definition of critical thinking. Critical Thinking in the Disciplines Critical Thinking in Psychology by Nancy Digdon Good account of how to frame questions precisely enough to make them subject to scientific investigation. This is an article on the website of the Committee for the Scientific Investigation of Claims of the Paranormal which provides a good account of how to assess scientific and paranormal claims. It incorporates scientific concepts and science-related issues as a vehicle for developing skills that will assist students throughout their educational and professional careers.