Homogeneous Grouping - Students are grouped for instruction by similar levels of achievement. Acheivement levels will still vary within homogeneous classes based on the number of students per grade level. A school with five classes per grade level may have two classes with high performing learners, two classes filled with average performing learners, and one classroom containing below average performing learners. A school with only two classes per grade level using homogeneous grouping would have a much wider range of within class achievement levels.
  • Ability Grouping is sometimes used to refer to more fluid forms of homogeneous grouping. Students groupings may vary by subject area based on individual student strengths. Student groupings may also vary over time as students move from one level to another.
  • Tracking is sometimes used to refer to more rigid forms of homogeneous grouping where students in the below average group or "track", tend to stay in that same group throughout their schooling. For whatever reason, whether it's the lower expectations for these classes, the higher concentration of discipline problems, the absence of academic role models, or the high proportion of students with special needs, students in these classes tend to fall further behind with little opportunity to move to a higher "track".
http://findarticles.com/p/articles/mi_hb6470/is_3_24/ai_n28919730/?tag=content;col1 - "Gouping the Gifted and Talented: Questions and Answers" Article summarizes much of the research and issues surrounding various forms of grouping.
http://findarticles.com/p/articles/mi_hb6470/is_3_24/ai_n28919731/?tag=content;col1 - "In search of reality: unraveling the myths about tracking, ability grouping, and the gifted." Article summarizes research on grouping practices as related to gifted students.
http://www.donet.com/~eprice/sdallan.htm - "Ability-Grouping Research Reviews: What Do They Say about Grouping and the Gifted?" Article summarizes some of the "original" research on grouping practices that debate and controversy have centered around for 20 years.
http://www.ericdigests.org/1993/groupings.htm - "The Effects of Homogeneous Groupings in Mathematics." Article summarizes some research results on homogeneous grouping in mathematics.
http://www.uoregon.edu/~adiep/grp.htm - "How Should We Group to Achieve Excellence with Equity." Article summarizes research on grouping as it relates to equity issues.
Tracking and Ability Grouping.pdf - This article summarizes some research on ability grouping and tracking with links to severals other articles on the topic.
**Tracking Article.pdf** - Recent article from ASCD about tracking and considerations to make when attempting to detrack.

Heterogeneous Grouping - Students are purposefully grouped for instruction to provide a wide range of achievement levels within each class at a given grade level. Gifted students, high performing learners, low performing students, and students with special needs are distributed relatively evenly across classrooms.
Heterogeneous_Grouping[1].pdf - Article from the National Middle School Association summarizes some research related to heterogeneous grouping.

Cluster Grouping - A hybrid of homogeneous and heterogeneous grouping where the gifted students at a given grade level are grouped within the same heterogeneous classroom.

http://www.gifted.uconn.edu/nrcgt/newsletter/spring96/sprng964.html - "Total School Cluster Grouping: An Investigation of Achievement and Identification of Elementary School Students". This research article presents the results of a study on the effects of cluster grouping on achievement.

Flex-Grouping - Another hybrid of homogeneous and heterogeneous grouping where students from heterogeneous classrooms are grouped in more homogeneous groups for some instruction based on student strengths. For example, for a lesson on finding the area of a triangle, students with strong geometric skills from multiple classrooms may be grouped together for the lesson with extention and enrichment. In similar fashion, students needing more help with spatial reasoning may be grouped together for that lesson.

Differentiated Instruction - Occurs when the teachers plans instruction to meet the variety of individual needs and performance levels within the classroom. Should occur regardless of the form of grouping used.
http://www.weac.org/Home/Parents_Community/differ.aspx - "Although Some Voice Doubts, Advocates Say Differentiated Instruction Can Raise the Bar for All Learners". Article makes suggestions as to what is needed for differentiated instruction to be successful.