Researchers and educators recognize that performance assessments and naturalistic observations are well suited for assessing young children's thinking abilities and understanding. The need to establish explicit evaluation criteria to guide assessment decisions has led to the widespread use of rubrics. Rubrics tend to channel assessors to look for features of task performance that are similar to or different from the description contained in the rubrics and ignore other aspects of task performance or thinking skills. This qualitative research adapted cognitive task analysis techniques typically used to study adult expert performance to explore young children's thinking skills and domain knowledge in their task performances. This innovative approach demonstrates that such techniques as thinking conversations and visual representations can be useful tools for eliciting and analyzing children's thinking processes and skills. These techniques allow for a more open-ended approach to exploring children's thinking competence than such commonly used methods as tests and criteria-based performance assessments. They can be employed to identify specific aspects of children's thinking competence for formative purposes or subsequent targeted assessment. The findings of this study could contribute to both research methodology and educational assessment methods. (Contains 3 figures and 1 note.)