Evidence sort and false results
Tue, Nov 10, 2026 · Week 12 · Genetics of Disease (Medical Interventions)
Today's goal: Sort case evidence by strength and explain how false positives and false negatives change a decision.
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Parallel case, not today's case: a 9 year old arrives with a sore throat and fever. The clinic runs a rapid antigen test for group A streptococcus, sends a throat culture, and takes a history.
Result | Strength | One-word reason
Throat culture positive at 24 hours | Strong | Confirmatory
Rapid antigen test, positive | Strong | Specific
Rapid antigen test, negative | Moderate | Insensitive
Fever reported at home, no thermometer | Weak | Unmeasured
Sibling said to have had strep, undocumented | Weak | Hearsay
One result that could be a false positive: the rapid antigen test. It detects strep antigen, and a child who carries strep in the throat without being ill from it can test positive while a virus is causing today's sore throat.
How that would change the patient's treatment: the child takes antibiotics they do not need, carrying the side effects and the resistance cost, and the actual viral cause stops being investigated.
One result that could be a false negative: the rapid antigen test again, failing in the other direction. It is meaningfully less sensitive than culture, which is why a negative rapid test in a child is normally backed up by a culture rather than believed on its own.
How that would change the patient's treatment: untreated group A strep is the case that can go on to rheumatic fever, so a false negative nobody backs up is the more costly of the two errors here.
The result I trust most: the 24 hour culture. It grows the organism itself instead of detecting a fragment of it, and it is the reference standard the rapid test is measured against.
How to use this: today's case is not this one. Sort your own results with the same three questions. What does this test actually detect, which direction can it fail in, and what does the patient lose when it does?
This model shows the level of evidence and organization needed to complete: Completes the evidence-sort task on a DIFFERENT case from today's, so it models the ranking and the false-result reasoning without handing over the sort students must do: every result ranked with a one-word reason, one plausible false positive and one false negative, the treatment consequence of each, and the result the student trusts most.
- Name the variables and include units.
- Enter observations without changing the raw values.
- Check labels, calculations, and patterns before interpreting the data.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Submit the evidence sort table and both false-result sentences on Schoology by end of period.
Turn in: Evidence sort on a parallel case
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Claim ceiling: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Naming which error a test design accepts and what that error costs the patient.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.