Question 72·Hard·Inferences
Recent efforts to chart long-term changes in the migratory patterns of the American robin rely heavily on the journals of nineteenth-century amateur naturalists. These observers, however, tended to record only the first robin they saw each spring, not the full arrival window for the species, and their notes were often prompted by chance rather than systematic surveys. Contemporary scientists must therefore adjust for the journals’ inconsistent coverage. Researchers who fail to do so ____
Which choice most logically completes the text?
For text-completion inference questions, identify the cause-and-effect relationship in the passage, then predict what the blank should do (state a consequence, explanation, or contrast). Track referents like “do so” to ensure you know what action is being referenced. Finally, choose the option that follows most directly from the passage without introducing a different focus (e.g., routes or population size) or adding unsupported specifics.
Hints
Clarify the referent of "do so"
Reread the sentence that begins "Contemporary scientists must therefore..." and make sure you know exactly what action "do so" refers to in the final sentence.
Focus on the nature of the historical data
Think about how the passage describes the nineteenth-century journals: Are they complete or incomplete? Systematic or chance-based? What kind of effect would using such data, uncorrected, have on research results?
Check the direction and tone of the outcome
Should the blank describe a positive discovery or a potential problem? Eliminate any options that sound too beneficial or that shift focus away from conclusions about migration timing over time.
Step-by-step Explanation
Identify the problem described in the passage
The passage explains that nineteenth-century observers often recorded only the first robin they saw each spring and that their notes were driven by chance rather than systematic surveys. That means the historical record is incomplete and inconsistently collected.
Determine what “fail to do so” refers to
The passage says scientists must "adjust for the journals’ inconsistent coverage." So "fail to do so" means fail to adjust for the historical journals’ gaps and inconsistency.
Evaluate what would happen without that adjustment
If researchers treat uneven, first-sighting journal notes as if they were comparable to systematic modern records, then any comparison of past vs. present timing can be skewed. The most logical result is that researchers could reach wrong conclusions about how migration timing has changed over time.
Choose the option that matches that consequence
The choice that directly states this consequence is "may draw inaccurate conclusions about how the robins' migration timing has shifted over time."