What type of assessment is most appropriate for a teacher to use at the beginning of the school year to determine students' decoding skills?

An informal phonics inventory is the most appropriate assessment to determine students' decoding skills at the beginning of the school year because it assesses a student's knowledge of phonics in a more flexible and direct manner. This type of inventory allows the teacher to identify specific phonetic skills that individual students possess, as well as areas where they may need additional support.

Using an informal phonics inventory provides insights into a student’s ability to recognize letter-sound relationships, which is foundational for decoding. This information can help teachers tailor their instructional approaches to meet the needs of each student, facilitating targeted support where necessary and allowing for differentiated instruction.

In contrast, a norm-referenced reading achievement test may provide some insights into students' reading levels compared to a larger population, but it may not give specific information about decoding skills alone. A summative curriculum-based measurement focuses on overall performance at the end of a learning period rather than at the beginning, making it less suited for initial assessments. An oral reading fluency test assesses the ability to read text smoothly and accurately but does not specifically target the underlying decoding skills as effectively as a phonics inventory does, limiting its utility for this purpose in the early assessment scenario.