There is excellent reliability and very respectable validity of the raters' scores. Reliability is determined by agreement between graduate students in their ratings of sites. Validity is determined by similarity between a graduate student's ratings of sites, based on the evaluation system described, and an expert's ratings of the same sites, based on the expert's opinion about the credibility of the information presented. To find out more about the WebGuide's evaluation system, write us at cfw@tufts.edu.