Teamformer

Teamformer builds student teams for you. The primary objective is to form as few teams as needed while ensuring constraints are met and encouraging WAM (weighted average mark/GPA) balance across teams. The system is a wrapper around a CP-SAT solver using Google OR-Tools.

Constraint handling includes:

✅ Each student is assigned to exactly one team

✅ Each team has between min and max students

✅ No team has only one student of a given gender (currently only M/F; other self-reported categories are ignored for balancing, but won't break anything)

✅ The number of teams used is minimized

✅ Students are only assigned to teams in the same lab as them

✅ Deviation from average WAM across the class is penalised

✅ Student preferences are favoured (positive and negative preferences now supported!)

The output is an Excel sheet with students and teams. Team numbers may not be sequential (drawn from 1:max_teams).

---

Data structure

Teamformer expects data in a spreadsheet like this (fake example):

	Student_ID	first_name	last_name	email	gender	wam	lab	Prefer_With	Prefer_Not_With
0	S1	Mark	Johnson	...	M	51.1	3	S2, S3	S4
1	S2	Donald	Walker	...	M	60.0	1
2	S3	Sarah	Rhodes	...	F	76.6	1	S1	S3
3	S4	Steven	Miller	...	M	54.2	2
4	S5	Javier	Johnson	...	M	75.3	4

Columns required/optional:

• Student_ID
• gender
• wam (optional)
• lab (optional)
• Prefer_With (optional): comma-separated list of Student_IDs the student wants to work with
• Prefer_Not_With (optional): comma-separated list of Student_IDs the student prefers not to work with

---

Install

pip install team-former

---

Run

team_former --input_file=students.xlsx --sheet_name=0 --output_file=teams.xlsx --wam_weight=0.05 --pos_pref_weight=0.8 --neg_pref_weight=0.8 --min_team_size=3 --max_team_size=5 --max_solve_time=30

---

How to get a good solution

Depending on your class sizes, demographics, and lab distribution, you may struggle to find a feasible solution. Options to address this include:

• Increase the max solve time — it may just be a matter of waiting longer
• Reduce or remove the WAM weight penalty
• Adjust the minimum team size — sometimes team balance is infeasible
• Adjust positive or negative preference weights (e.g., set pos_pref_weight=0.5 if you want preferences to have less influence)

---

Preference handling

When using preference columns, Teamformer will attempt to:

• Keep students together if listed in Prefer_With, unless it conflicts with other constraints.
• Avoid assigning students together if listed in Prefer_Not_With.

Preferences are not strictly enforced (they are "soft" constraints), but they strongly influence the solution when weights are set high.

---