What should be the nature of reading selections used in an informal reading inventory?

The nature of reading selections used in an informal reading inventory should be increasingly difficult to effectively assess a student's reading capabilities. This approach allows educators to identify the specific level at which a student can read independently, as well as where they may require additional support. Through progressively challenging selections, educators can determine a student's current reading level and their potential to tackle more complex texts, which is integral to planning appropriate instructional strategies.

Using selections that vary in difficulty helps in pinpointing a student's reading strengths and weaknesses. It also aids in understanding how well they might perform with texts that are beyond their current reading level, offering insights into their growth potential.

In contrast, ensuring that the reading materials are the same for all students does not account for individual differences in reading abilities. Focusing solely on independent reading levels would not provide a full picture of what a student can do with support, while using instructional reading levels may limit the assessment of a student's maximum capability. Thus, opting for increasingly difficult readings is crucial for accurately gauging and subsequently supporting a student's reading development.