Research brief on elements of trimester scheduling: The Principal's Partnership, and the Union Pacific Foundation.
Why do a trimester schedule?
Summary of Findings: With the advent of block scheduling, many high schools conducted research on utilizing that plan in a trimester format. There appeared to be three issues that most schools faced: How to provide substantive instructional time that was not fragmented?; How does the school climate contribute positively to students' learning?; and How to provide the appropriate amount of instructional time so that each student can learn in the best ways for him/her? Breaking Ranks suggested that: curriculum should offer essential knowledge that makes connections to real life; instructional strategies should actively engage students in their learning; the environment should be receptive to the learners and educators; time and space be reexamined and utilized to best meet the needs of the students; and all stakeholders should be accountable for assessment of the instructional program.
http://www.principalspartnership.com/trimester.pdf

Ozaukee High School Trimester Scheduling Plan: Sample schedule, advantages of 5 period schedule.
http://ohs.nosd.edu/display_page.asp?pID=220

Detailed schedules and resources on trimester scheduling from Spring Lake, Michigan.
http://www.trimesters.org/

Video: Looking at the Trimester Schedule, with Kent DeKoninick  an Indiana Information Network video.
http://www.doe.state.in.us/media/video/ipla/DVS_a_03.html

When big seems small - NWREL on how Beaverton High School made a transition to small learning communities using trimesters.
http://www.nwrel.org/nwedu/10-01/when/

Southridge High School transformation - NWREL on Southridge High School and its trimester schedule and other elements to make a big school seem small.
http://www.nwrel.org/request/2003sept/southridge.html

Southridge High School and the Trimester Schedule
http://www.nwrel.org/scpd/sslc/descriptions/southridge/pdfs/trimester_scheduling.pdf