Assessing children's competency to take the oath in court: The influence of question type on children's accuracy.

This study examined children's accuracy in response to truth-lie competency questions asked in court. The participants included 164 child witnesses in criminal child sexual abuse cases tried in Los Angeles County over a 5-year period (1997-2001) and 154 child witnesses quoted in the U.S. state and federal appellate cases over a 35-year period (1974-2008). The results revealed that judges virtually never found children incompetent to testify, but children exhibited substantial variability in their performance based on question-type. Definition questions, about the meaning of the truth and lies, were the most difficult largely due to errors in response to "Do you know" questions. Questions about the consequences of lying were more difficult than questions evaluating the morality of lying. Children exhibited high rates of error in response to questions about whether they had ever told a lie. Attorneys rarely asked children hypothetical questions in a form that has been found to facilitate performance. Defense attorneys asked a higher proportion of the more difficult question types than prosecutors. The findings suggest that children's truth-lie competency is underestimated by courtroom questioning and support growing doubts about the utility of the competency requirements.