Benchmark Quizzes in Organic Chemistry

[kevin_revell]

What should every student who passes my organic class be able to do?

Joshua Ring is an associate professor of organic chemistry at Lenoir-Rhyne University.  This past summer, I had the opportunity to hear Joshua give a talk at BCCE.  He posed this question, and offered an innovative solution, recently featured in C&E News.   In essence, Joshua flips his class, then uses a series of benchmark quizzes built around the learning objectives.  The quizzes are pass-fail.  He gives no partial credit.  However, students have multiple attempts to demonstrate mastery.   In his class, there are about 7 essential benchmarks that students must pass in order to pass.  There are 14 additional benchmarks – the number of these that the student is able to pass determines the final grade.

The Modification

Although the class structure at my school is much different than at Lenoir-Rhyne, I was intrigued.  I therefore designed a modified benchmark system for my class.  We began with six benchmarks:

1. Structure – Draw Lewis structures with correct formal charge and electron counts; identify electronic & molecular geometries & hybridization
2. Nomenclature – Correctly name key molecules, including alkanes/alkenes/alkynes
3. Function – identify acidic and basic sites, nucleophiles, electrophiles
4. S_N1, S_N2, E1, E2 - Show complete arrow-pushing mechanisms for these four fundamental processes.
5. Reactions of Alkenes - Show products from addition reactions to alkenes.
6. Spectroscopy - Identify major features from NMR/IR/MS

The benchmarks were pass-fail, but students had more than one attempt to take them.   The class also included an online homework grade.  However, in order to “unlock” their homework grade, they had to pass five of the six benchmarks.

Implementation 

Here is one version of the first benchmark quiz:

Students had to be essentially 100% right to pass.  The first time, only about 44% passed.  The next time it was offered, another 30% passed.  Eventually, nearly everyone in the class passed the exam.

The thing I liked about this was that it stressed to students the importance of learning the fundamentals.   And it seemed to pay off as the class wore on – I saw fewer problems with identifying electronic geometry or goofy formal charges on mechanism questions. 

Unfortunately, I could not fully implement the benchmark scheme.  Because of the coverage of our text, too many of my benchmarks landed later in the semester, and, pressed for time, I was forced to cut the benchmark quizzes short, and also to remove the tether to the homework grade.  Despite the fizzle at the end, I was pleased with this first attempt.  I feel that my students are better prepared heading into organic 2 than they have been in the past.  The pass-fail approach drove students to practice the material until they got it down. 

Outlook

I am not teaching organic next semester, and so won’t have an immediate opportunity to improve on the approach with that course.  However, I plan to institute benchmarks for introductory chemistry.  I am planning on 12-14 benchmarks (essentially one per chapter), closely tied to the chapter learning objectives.  Students will take benchmarks at the beginning of lab each week.  I’m excited to see how it goes!