STEM PRACTICE AND EVIDENCE WORKBENCH
Calculate signed percent change from a nonzero baseline and audit both numerical magnitude and direction language.
Review output
Load the worked example to inspect realistic inputs, or enter anonymous classroom or laboratory evidence. Results remain in this browser tab until you copy or download them.
Transparent method
Signed percent change equals new minus original divided by the absolute nonzero original value times one hundred. A positive result is increase, a negative result is decrease, and zero is no change. The entered tolerance compares numerical results while the direction label is audited separately. Supported means both the learner percentage and direction match the disclosed baseline calculation. A correct direction with wrong magnitude often points to a denominator or arithmetic issue. Review whether percent change, percent difference, percentage-point change, growth factor, or repeated compound change is actually requested before interpreting a result.
Confirm the question, source, units, notation, response coding, model assumptions, and review threshold. Keep an unchanged copy of the original evidence.
Run the worked example, inspect every intermediate row, and compare it with a hand calculation, diagram, representation, or approved subject method.
Record the method, assumptions, units, classifications, and flagged rows. Verify the editable report independently before educational or laboratory use.
How to interpret the result
Use when percent-change errors may come from the denominator, sign, direction label, or confusion with percentage points. The workbench checks one original-to-new comparison at a time. It does not choose the baseline, compare incompatible periods, annualize a rate, handle a zero baseline, infer causal meaning, or judge whether a percentage is practically important.
Moving from 80 to 100 is a 25 percent increase, while 50 to 40 is a negative 20 percent change and a decrease. Identical values produce zero and no change. The final row moves from 20 to 25, so its direction is right but its 20 percent value uses the wrong relationship and is flagged.
Signed percent change equals new minus original divided by the absolute nonzero original value times one hundred. A positive result is increase, a negative result is decrease, and zero is no change. The entered tolerance compares numerical results while the direction label is audited separately.
Supported means both the learner percentage and direction match the disclosed baseline calculation. A correct direction with wrong magnitude often points to a denominator or arithmetic issue. Review whether percent change, percent difference, percentage-point change, growth factor, or repeated compound change is actually requested before interpreting a result.
Do not divide by the new value, subtract percentages without their bases, drop a negative sign, call 40 to 50 the same signed change as 50 to 40, confuse a ten-point change with ten percent, or invent a result from zero baseline. Label original and new, write the fraction, and check with a multiplicative factor.
Learning boundary
This browser-local workbench applies only the disclosed rules. It cannot diagnose a learner, certify an experiment, or replace teacher, laboratory, and safety judgment.
Review checklist
Practical questions
No. Processing occurs in the current browser tab. Avoid personal information and retain authoritative records only in the approved school system.
No. It describes entered evidence under one disclosed rule. Review reasoning, uncertainty, access, and several evidence sources.
Treat it as an editable calculation aid. Show your own reasoning, cite required sources, and follow course and academic-integrity rules.
YOUR NIRMION
