If a claim does not carry its evidence, it does not go on the board. The whole rule fits on a poster.
Six letters, one habit
The evidence classes are a fixed set of tags a student writes next to any claim in class. The tags are the same across subjects, so a habit built in social studies transfers into biology and back into English. The set:
- A: empirical in-session. I ran it here, in front of you, and it produced this result.
- B: code or inspection. The source is open, the steps are re-runnable, and I can walk you through them.
- C: configuration or integration. The claim is about how two things are wired together, and the wiring is documented.
- E: expert citation. A named author, in a named venue, said this, and here is the reference.
- F: falsifier present. Here is the specific observation that would make the claim wrong.
- U: unverified. I believe it, but I cannot show you the receipt yet.
Six letters. The instruction to students is small and hard: every claim on the board, in the essay, and in the lab report carries one of these letters in parentheses right after it. If the letter is U, that is fine, and it stays U until it can be moved. The point of the tag is not to shame; it is to make the epistemic status visible so the class can talk about it.
The scheme is our house style for evidence, and it lines up with how careful writers distinguish empirical results, code artifacts, and citations from the surrounding literature (Class E, per Parr, Pezzulo, and Friston, 2022). We just made the labels short enough for a seventh grader.
Examples across subjects
The tags are meant to travel. A handful of worked cases, so a teacher can hand this to a class on Monday.
Science lab. "Adding salt to the water raised the boiling point in our beaker (Class A). The published relationship between molality and boiling-point elevation predicts this (Class E). If a fresh trial with distilled water gave the same reading, the claim would be wrong (Class F)."
History essay. "The 1918 pandemic reshaped municipal public-health authority in several US cities (Class E, citing the assigned reading). Whether that authority survived past the 1930s in our county is not in the sources I checked (Class U). Here is the archive I would open to move this toward E."
Mathematics. "For any prime p greater than 2, p is odd (Class B, since the definition and argument are inspectable). A counterexample would be an even prime larger than 2 (Class F). None exists, and the argument shows why."
Computer science. "Our sorting function returns a sorted list on the four test inputs we wrote (Class A). The code is here, fifteen lines (Class B). The test harness inside the classroom repo is set up as documented in the workbench (Class C). If the function is called on an empty list and throws, the claim is wrong (Class F)."
English. "The narrator in this chapter is unreliable, based on the three passages I marked (Class B, since the passages are visible and re-readable). A reviewer who reads the same passages and finds the narrator consistent would weaken the claim (Class F). Whether the author intended the unreliability is not something I can show from the text alone (Class U)."
Notice the shape. The tag pushes the student to say what kind of thing the claim is, and to name the move that would knock it down.
What changes when the tags are graded
Once the tags are part of the rubric, three things shift.
One, students stop writing bare assertions. A sentence without a class attracts a quiet pencil mark, and the student learns to add the class early rather than late. The friction is low, and it compounds.
Two, U is no longer a failing state. A student who writes "(Class U)" honestly is doing the subject correctly. The follow-up question becomes "what would move this from U toward E, B, or A." That is the productive question.
Three, the classroom argument stops being about vibes. Two students who disagree can point at each other's tags and ask, "yours is Class E, mine is Class A; whose scope is wrong." That is a conversation a middle-schooler can have, and it is the same conversation a graduate student has.
The wiring between the rubric, the LMS, and the printed rubric card is documented in the workbench setup, so a teacher does not invent it from scratch (Class C).
The small poster that goes on the wall
One page. Six letters, one line each, in the student's own handwriting when possible. Under the six lines: "every claim on the board, in the essay, in the lab report, carries one of these." A piece of classroom furniture that teaches the subject every time a student looks up.
Where to go from here
- Read curriculum-gates-that-teach-thinking for the checkpoints that use these tags inside a unit.
- Read a-rubric-that-rewards-falsifiability for the grading language that turns Class F into points on the page.
- Read honesty-in-classrooms-the-ai-authorship-fence for how the fence and the tags sit next to each other on the same wall.
- Book the Workshop to see the tags in a live session with a class.