The Mosaic Project · weekly grouping

Mosaic Grouper

Upload the week's roster and the teachers' stick-together list. The tool builds a set of mixed sharing groups and single-gender cabins, keeping required kids together while spreading schools, genders, and backgrounds across every group. Only have the stick-together list? You can build sharing groups from that alone — the roster is inferred (cabins need a roster with gender).

How the groups are built & how to check it

The grouper follows the same fixed rules every time. Here is exactly what it does, what it promises, and how you can confirm it on your own kids — you don't have to take the method's word for it.

  1. Read the two files

    It matches your column headers loosely, so a header like “Gender (M, F)” still counts as the gender column. Each child on the stick-together list is paired to their roster entry by name to find their school.

  2. Lock in the teacher groups

    Children a teacher marked with the same group number (from the same school) become one unit that always travels together. Everyone else is a unit of one. Because two teachers at different schools might both write “Group 1,” units are identified by school and number, so they're never accidentally merged.

  3. Build the sharing groups

    It places the units one at a time, largest first, each time choosing the group that keeps things most balanced — even sizes, a spread of schools, an even boy/girl split, and a mix of backgrounds. Then it runs several thousand small trial swaps between groups, keeping any swap that improves the overall balance and undoing any that doesn't. This “place, then polish” approach reliably settles on even, well-mixed groups.

  4. Build the cabins

    Cabins are single-gender, so each teacher unit is first split into its boys and its girls (each kept together). For each gender it uses 5 or 6 cabins — whichever divides that group most evenly — never more than nine children each, and runs the same place-then-polish balancing — spreading schools and keeping sizes even, with no gender mixing.

Guaranteed every run

  • Exactly the number of sharing groups you choose; every child appears once and only once.
  • Every child a teacher grouped stays with their group — split by gender only where a cabin physically requires it.
  • Every cabin is a single gender and never holds more than nine children.
  • Group and cabin sizes are as even as the teacher groups allow.

Actively balanced

  • Schools are spread across every group rather than clustered.
  • Sharing groups are balanced between boys and girls.
  • Backgrounds (race) are mixed across groups.

When you build groups, a Checks panel appears at the top of the results. It re-examines the groups the tool just produced and confirms each guarantee above on this week's actual children — green means verified. There are many valid ways to satisfy the rules, so “Try another arrangement” gives you a different layout that passes the same checks.