How to solve SAT Command of Evidence questions

Command of Evidence questions give you a claim and ask which piece of evidence best supports, illustrates, or weakens it. They come in two versions. Textual questions offer quotations or hypothetical research findings, and quantitative questions offer data from a table or graph. The skill sits in the Information and Ideas domain, about 26% of the Reading and Writing section, or roughly 12 to 14 questions shared among three skills. You will usually see several Command of Evidence questions per test, and at least one of them typically includes a table or graph.

What the questions look like

• Illustrate a claim with a quotation. The passage makes a claim about a poem, novel, or speech, and the question asks, "Which quotation from the poem most effectively illustrates the claim?" Four quotations follow.
• Support or weaken a hypothesis. A passage describes a researcher's hypothesis, and the question asks, "Which finding, if true, would most directly support the researcher's hypothesis?" Some versions ask which finding would weaken it instead.
• Use data. The passage refers to a table or graph and ends with a blank or a claim. The question asks, "Which choice most effectively uses data from the table to complete the text?" or which choice best illustrates the claim.

Step-by-step method

1. Find the claim. It is usually in the last sentence or two, often attached to a name, as in "Nand hypothesized that..."
2. Break the claim into its parts. If the claim says a speaker feels both pride and regret, the evidence must show both. If a hypothesis says A causes B, the evidence must connect A and B.
3. Predict what good evidence would look like before reading the choices.
4. For quantitative questions, apply two filters in order. First, cross out any choice that misstates the data. Then, from the accurate choices, keep only the one that addresses the claim.
5. For support or weaken questions, imagine the finding is true. Decide whether it makes the hypothesis more likely, less likely, or no different, and check which direction the question wants.
6. Pick the choice that addresses the specific claim most directly, not the topic in general.

Worked example

Agricultural researcher Priya Nand grew four bean varieties under normal watering and under reduced watering. She hypothesized that varieties with deep root systems lose less yield when water is limited than varieties with shallow root systems do. The data in the table support this hypothesis, since ______

Which choice most effectively uses data from the table to complete the text?

A) Bell produced the highest yield of any variety under normal watering.
B) the two deep-rooted varieties each lost 6 kilograms per plot or less under reduced watering, while the two shallow-rooted varieties each lost at least 14 kilograms per plot.
C) Cora and Dane each produced less than 35 kilograms per plot under reduced watering.
D) Dane produced a higher yield under reduced watering than Cora did.

Answer: B. Start with accuracy. Arlo fell from 40 to 34, a loss of 6, and Cora fell from 38 to 33, a loss of 5. Bell fell from 42 to 25, a loss of 17, and Dane fell from 36 to 22, a loss of 14. So B is accurate. Choice D is not, since Dane's 22 is lower than Cora's 33.

Now check relevance. A and C are both true, but neither compares how much yield the deep-rooted and shallow-rooted varieties lost. A is about normal watering only. C groups a deep variety with a shallow one, so it can't show a difference between root types. Only B links root depth to yield loss, which is exactly what the hypothesis is about.

Here is a textual version.

Many songbirds sing most intensely in the first hour after sunrise. Biologist Tomas Lindqvist hypothesizes that males of one warbler species concentrate their singing at dawn because sound carries farther in the cool, still air of early morning than in the warmer, windier conditions later in the day.

Which finding, if true, would most directly support Lindqvist's hypothesis?

A) Female warblers of this species are most active in the early morning.
B) On unusually warm, windy mornings, the males sang less at dawn than they did on cool, calm mornings.
C) The males sing more often in spring than in late summer.
D) Several other bird species in the same forest also sing mostly at dawn.

Answer: B. The hypothesis links dawn singing to the conditions that help sound carry. If the birds cut back on dawn singing when those conditions disappear, that ties the behavior to the cause Lindqvist proposes. D stays on topic, but other species singing at dawn says nothing about why this species does. A and C bring in factors the hypothesis never mentions.

Common traps

• Accurate but irrelevant. In data questions, most wrong choices state the numbers correctly. Being true is only the first filter. The answer must also prove the specific claim.
• Half the claim. If a claim has two parts, a quotation that shows only one of them is wrong, even if it fits that part perfectly.
• Wrong direction. Read the question for "support" or "weaken." Also check that a comparison runs the way the claim needs. If a hypothesis predicts that A is larger than B, a choice showing B larger works against it.
• Same topic, no logical link. Choice D in the warbler example mentions dawn singing, which feels relevant. It doesn't test the reason for the behavior, so it doesn't support the hypothesis.
• Misread graphs. Mixing up two lines in a legend or reading a percent as a raw count are common slips. Read the title, axis labels, units, and legend, then find the exact bar or cell for each number.

Quick check

• Can you restate the claim in a short phrase that includes every part of it?
• For a data choice, is it accurate, and does it address the claim?
• For a finding, would it make the hypothesis more likely to be true? For a weaken question, would it make the hypothesis less likely?