One hundred thirty-eight second graders, identified by their teachers as "poor readers with incomplete phonics skills" were given four specially constructed tests of phonics skills: a context test over meaningful but visually unfamiliar words, an isolated sounds test, a McKee type multiple choice test, and a word completion test. Eighty of the cases were also tested with the Burnett Reading Survey Test and a Test of Cognitive Abilities. The group was normal with respect to intelligence but were poor readers. Scores on the context test were significantly lower than those on the other phonics tests but were correlated higher with the Burnett Word Identification and Word Meaning Tests than any of the others. The factor measured by the context test accounted for a much higher proportion of the variance in the Burnett subtests than did any of the other phonics tests. The context test approach was deemed to be a much more valid diagnostic technique. The patterns of responses on the phonics tests indicated that the Isolation, McKee, and Word Completion tests measure a less mature level of skill than the Context test. This suggests that they might be used to determine if prerequisite abilities have been developed. (Author)