Final answer:
The optimal method for forming reading instructional groups is through teacher observation and informal assessments, as they consider the unique learning needs of each student and provide a nuanced approach beyond what standardized tests can offer.
Step-by-step explanation:
The best way to determine reading instructional groups in a classroom with a wide range of skills and abilities is using teacher observation and informal assessments. This method allows instructors to account for the students' diverse levels and learning needs, providing a flexible and adaptive approach. Standardized tests can offer a snapshot of a student's ability, but they might not reflect the full range of a student's reading skills or their ability to work in a group setting. Observations and informal assessments can be more responsive to the day-to-day changes and nuances of student learning.
Practice and assessment strategies, such as grasp checks and performance tasks, align with this approach by allowing for ongoing formative assessment that informs instruction. This helps in creating groups that maximize student learning potential. Instead of relying solely on numerical data or random assignment, which can be disengaging, teachers actively involve students in their learning journey.
Making observations and interpreting them is a skill that should be encouraged in the learning environment. Relying too much on standardized testing may hinder the development of these skills. Therefore, a balanced approach to assessment and grouping that incorporates teacher insights is beneficial.