Logical Reasoning

PT124 · S2 · Q17 Reporter: A team of scientists

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Reporter: A team of scientists has recently devised a new test that for the first time accurately diagnoses autism in children as young as 18 months old.

Conclusion

Autistic children can now benefit much earlier in life from the available treatments.

Evidence

A new test for autism caught all 10 truly autistic children in a sample of 16,000 — but also wrongly identified 2 children as autistic.

Evaluate

To say children "benefit" from earlier treatment, we need to be okay with the test triggering treatment in some children who are not actually autistic. The test produces some false positives. The argument needs the assumption that even with these false positives, the early-treatment policy is still a reasonable basis for treatment decisions.

Goal

Find the assumption that supports treating children based on the test even though it sometimes errs on the side of false positives.

17.

Which one of the following is an assumption on which the reporter's argument depends?

  1. No test intended for diagnosing

    Out of Scope

    The argument is about whether autistic children can now benefit earlier from treatment. Whether other early-diagnosis tests existed before is irrelevant. Negate this answer (some other test existed before) and the conclusion still follows — children can still benefit earlier with the new test.

    13% picked this

  2. Correct

    A diagnostic test that sometimes

    Why this is right

    This is the assumption the argument needs. The test produces some false positives — 2 children flagged who are not autistic. For the conclusion (autistic children can benefit earlier from treatment) to follow, the false positives must not undermine using the test to guide treatment. Negate this answer — "a test with false positives cannot be a reasonable basis for treatment decisions" — and the conclusion collapses, because no one would treat based on this test. The argument depends on this.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

    68% picked this

  3. The new test can be

    Bad Assumption

    The argument does not need the test to work for all children regardless of verbal skills. The study already showed it caught 10 out of 10 autistic children in a sample of 16,000 — strong evidence the test works in practice. Negate this answer (the test does not work on all children regardless of verbal skills) and the conclusion still holds: the test still allowed those 10 (and presumably future similar children) to be diagnosed and treated earlier.

    1% picked this

  4. Those children incorrectly identified as

    Bad Assumption

    The conclusion is about autistic children benefiting from earlier treatment. Whether the misidentified children will be unaffected by autism treatments is not required for the conclusion to hold. Negate this answer (misidentified children will be adversely affected) and the original conclusion still works for the actually autistic children — the question of harm to false positives is a separate concern from whether autistic children benefit. The argument does not depend on this.

    15% picked this

  5. There was no reliable evidence

    Out of Scope

    The argument concludes autistic children can now benefit earlier — it does not need the claim that no prior evidence existed about autism in children this young. The conclusion is forward-looking; the historical claim about prior evidence is not necessary. Negate this and the argument is unaffected.

    3% picked this

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