Monday, June 20, 2022

Heterogeneous Lab Groups

Rationale and method for creating lab groups that consist of four students, each from a different performance quartile

Paperwork Reduction
Most teachers don’t want to painstakingly grade every lab report from every student in each physics (or any science) class. Students within a lab group tend to produce highly similar lab reports, anyway. You really don’t need to look at more than one lab report from each lab group.

Limited Engagement?
Each student should be fully engaged in the lab activity and feel invested in writing his or her own report. So don’t allow each group to produce one report to be turned in. Each student needs to be responsible for completing his or her own report.

No Group Member Left Behind
Pick up one report from each group. But do so only when the activity is over and all the reports are complete. Let the students know which group member is to turn in the lab no sooner than the time at which the report is to be turned in. Brighter, faster students cannot race ahead of slower students since it may well be one of the slower students whose report will be graded.

No Cliques
Students naturally prefer to sit with their friends. This doesn’t always yield the best results. As the grown-up in the room responsible for the instructional program, you have the freedom (if not the obligation) to improve the environment. Here’s how you can create lab groups consisting of students from across the performance spectrum within the class.

The Process for Creating Heterogeneous Groups
Once you have some classroom performance data on your students (quizzes, tests, labs), sort them from top student to bottom. Then break the class into quartiles.

Let students within a single quartile populate distinct lab groups. You can do this and still allow students some level of choice in where they sit. Here’s how I do it.

I might have 32 students in a class. So they break up into quartiles of 8 students. While the students stand in the back of the room, I’ll read off the names of all the students in one of the quartiles and tell them to take up positions in different lab groups from each other. At this point, each lab group has one member. Repeat with the other three quartiles. For privacy reasons, it is best that the students don’t know the scheme, so be random in your ordering of the quartiles (don’t start with the 1st quartile and end with the 4th; try 2nd-4th-3rd-1st, for example). The process takes only a few minutes.

The end product is that each group has a student from the 1st, 2nd, 3rd, and 4th quartiles. Each group is heterogeneous in terms of class performance.

The geometry of my classroom seating arrangement makes it fairly simple to assign each seat within a group a number between 1 and 4. Each student knows his/her seat number.

When it comes time to pick up a lab report, I randomly generate a number between 1 and 4. The number that comes up is the seat number of the student who turns in the lab.

The turned-in lab is decided by seating location. You most certainly don’t want to say anything like, “Would the smart student in each group please turn in his/her lab report.” Students should have no idea which quartile they’re in.

So the turned-in lab report may come from the top student in the group, and it may come from the bottom student in the group. Either way, every member of the group will be given the score earned by the turned-in report.

Time to Regroup
A legitimate student concern arises if someone in the group is not a team player. Counsel any such student if the behavior is observed. Also allow for quartile-based regrouping at regular intervals. I regroup my classes every 20 class days, using updated performance data.

I developed this process in the early 2000s. In the 2010s, I found myself preferring post-lab quizzes to grading lab reports. But I continued with heterogeneous lab groups and the monthly churn.

Sometimes students maintained their performance level status and worked to remain in their lab group through the churn. This didn't bother me per se, but sometimes I wanted a more thorough churn. To force a complete churn (your new group has none of your old partners), try this:

Make each "seating group" (in my case, eight students) out of two existing lab groups. For me: Seating Group 1 was Lab Groups A + B, Seating Group 2 was Lab Groups C + D, etc.. At the end of the process (for a 32-student class with eight lab groups), no one is in a new group with an old member.

Other randomizing variations is to sort the roster by student ID number, and create seating groups from that list.

Homogeneous Lab Groups (in May)
On the final churn of the year, I imposed the seating chart. And I flipped the script completely. I sorted my roster by performance and divided them four students at a time. I put the top-performers in the back of the room and the bottom performers in front. Again: no disclosure of what, exactly, I was doing and why.

But those groups were collections of students that may have never worked together in class before. Or sat where they had before. Whatever lab group dynamic might have settled in for some students was disrupted a bit in May.

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