What statement about screening measures in literacy assessment is true?

Screening measures play a critical role in identifying students who may be at risk for literacy difficulties. The correct statement indicates that many screening measures can be considered diagnostic. This means that while screening assessments can provide valuable insights into a student's reading abilities and highlight areas needing further evaluation, they do not function as definitive diagnostic tools across the board.

Screening measures are generally designed to quickly assess a student's skills and identify those who require more comprehensive evaluation. They can indicate potential reading difficulties, but they do not provide detailed diagnoses about specific reading disorders. Consequently, while some screening measures may have diagnostic qualities—suggesting areas for further investigation—they are not universally diagnostic in nature.

Thus, option C effectively captures the nuanced role of screening measures in educational settings. It acknowledges their importance without overstating their capabilities, which is key in understanding how to best support students' literacy development.