SAT Reading and Writing: Command of Evidence — Quantitative

Learn to interpret graphs, charts, and tables to effectively use quantitative data as evidence on the SAT Reading and Writing section

Domain: Information and Ideas Frequency: 8-10% of questions Skills: Data + Reading

By NUM8ERS Test Prep Team | Updated October 2025 | 22-minute read

What are Command of Evidence: Quantitative Questions?

Definition: Command of Evidence: Quantitative questions test your ability to interpret data from graphs, charts, or tables and use that data to complete a sentence or support a claim about a scientific, social, or historical topic. Unlike textual evidence questions, these require you to read visual data and connect numerical findings to written arguments.

These questions combine two skills: data interpretation (reading graphs accurately) and evidence evaluation (determining which data point best supports a specific claim). You'll encounter 4-6 of these questions on your SAT, always paired with scientific or informational passages.

🎯 Question Format

A typical quantitative evidence question includes:

A graph, chart, or table presenting quantitative data
A short passage (1-2 paragraphs) providing context about the research or topic
An incomplete sentence that makes a claim about the data
Four answer choices that complete the sentence using different data points

Standard Question Stem:

"Which choice most effectively uses data from the [graph/table] to complete the [statement/example]?"

📊 Types of Visual Data You'll See:

Bar graphs — Compare quantities across categories
Line graphs — Show trends and changes over time
Tables — Display multiple variables in rows and columns
Pie charts (rare) — Show proportions/percentages of a whole
Scatterplots (rare) — Display relationships between two variables

🔍 Key Differences from Math Section Data Questions

Aspect	Reading & Writing	Math Section
Primary Skill	Selecting data that supports written claims	Calculating values, solving equations with data
Calculations Required	Minimal or none (mostly reading values directly)	Extensive (percentages, means, rates, etc.)
Focus	Understanding the "story" the data tells	Numerical precision and mathematical operations
Answer Format	Complete a sentence with data-based statement	Provide numerical answer or select calculated value

💡 Key Insight: On Reading & Writing questions, you're not solving math problems—you're using data to complete written arguments. The focus is on evidence selection, not calculation.

📖 How to Read Graphs Efficiently

Before attempting the question, spend 10-15 seconds orienting yourself to the visual data:

1. Read the Title

What topic does this graph address? What's being measured?

2. Check Axis Labels

What do the x and y axes represent? What units are used?

3. Identify the Scale

How are intervals marked? Is there a key or legend?

4. Find the Pattern

What's the overall trend? Highest/lowest values? Big changes?

Top Tips: Mastering Quantitative Evidence Questions

🎯 The 4-Step Strategy

Step 1: Skim the Graph First

Before reading the passage, quickly scan the visual data to understand its structure. Note: what's being compared, measured, or tracked over time. Don't try to memorize numbers—just get the big picture.

Example: "This bar graph compares energy consumption across 4 countries. Germany has the lowest, China has the highest."

Step 2: Read the Paragraph for Context

The passage provides the "story" the data is telling. Understand the researcher's claim, hypothesis, or main point. This helps you identify what kind of data will support it.

Ask: "What is this passage arguing or demonstrating with this data?"

Step 3: Identify What the Blank Needs

Read the incomplete sentence carefully. What type of data would complete it logically? Are you looking for:

A comparison (higher/lower, more/less)?
A specific value or range?
A trend (increase/decrease over time)?
An extreme (highest, lowest, most dramatic change)?

Step 4: Test Each Choice Against the Graph

Go back to the graph and verify each answer choice. The correct answer will:

Accurately reflect values shown in the graph
Match the claim's focus and scope
Be the most specific and relevant option

⚠️ Warning: Wrong answers often cite real data from the graph but support a DIFFERENT claim than what's stated.

⚠️ Common Pitfalls to Avoid

1. Misreading Graph Scales

Always check the scale carefully! A graph might count by 5s, 10s, 100s, or 1000s. Misreading intervals leads to selecting data that looks right but cites wrong values.

2. Choosing Irrelevant (But True) Data

The SAT loves to include answer choices that cite accurate data that doesn't support the specific claim. Just because it's in the graph doesn't mean it's the right answer.

Example: If the claim is about "rapid growth," citing steady/slow growth data (even if accurate) is wrong.

3. Confusing Categories or Time Periods

Tables and multi-variable graphs require careful attention. Make sure you're reading data from the correct row, column, line, or bar. It's easy to accidentally cite data from the wrong category.

4. Overthinking Simple Data

These questions don't require complex calculations. If you find yourself doing elaborate math, you're probably overcomplicating it. Most answers involve directly reading values or making simple comparisons.

5. Ignoring Units of Measurement

Pay attention to whether values are in percentages, thousands, millions, degrees, etc. An answer might state "20" when the graph shows "20,000" or confuse percentages with raw numbers.

💡 Pro Tips from High Scorers

Find the "story" first: Data tells stories about change, comparison, relationships. Identify what narrative the passage highlights.
Look for extremes: Words like "most," "least," "dramatic," "significant" often point to highest/lowest values or biggest changes
Match comparison types: If the claim compares two things, your answer should too. If it describes a trend, find data showing that pattern.
Be flexible with phrasing: The data might show "X doubled" but the answer says "X increased by 100%"—these mean the same thing
Eliminate obviously wrong: Cross out choices that cite wrong categories, time periods, or values that don't exist in the graph
Trust your reading of the graph: If you carefully checked the scale and labels, don't second-guess your data interpretation
Time management: Don't spend more than 90 seconds on these. If stuck, use process of elimination and move on

Worked Example: Bar Graph

Scenario:

Researchers studied how different teaching methods affect student test scores in mathematics. They compared traditional lecture-based instruction with interactive problem-solving sessions across four schools. The graph below shows average test score improvements (measured in points gained) after 12 weeks of instruction.

Average Test Score Improvement by Teaching Method

School A:
Traditional: ████████ (8 points)
Interactive: ████████████████ (16 points)
School B:
Traditional: ██████ (6 points)
Interactive: ██████████████████ (18 points)
School C:
Traditional: ██████████ (10 points)
Interactive: ████████████ (12 points)
School D:
Traditional: ████████████ (12 points)
Interactive: ██████████████████████ (20 points)

Note: Each ██ = 1 point improvement

The researchers concluded that interactive problem-solving sessions consistently produced greater learning gains than traditional lectures. To support this conclusion, they noted that the difference between teaching methods was particularly pronounced at _______

Question:

Which choice most effectively uses data from the graph to complete the statement?

A) School C, where traditional instruction resulted in a 10-point gain and interactive instruction resulted in a 12-point gain.

B) School B, where traditional instruction resulted in a 6-point gain while interactive instruction resulted in an 18-point gain.

C) School D, which had the highest interactive instruction score of 20 points.

D) School A, where both teaching methods produced improvements greater than 5 points.

Step-by-Step Solution:

Step 1: Skim the Graph

What I see: A bar graph comparing two teaching methods across four schools. Interactive sessions (second bar for each school) are consistently longer than traditional bars, meaning higher score gains.

Step 2: Understand the Claim

The claim: "The difference between teaching methods was particularly pronounced"
What I need: Data showing the BIGGEST gap between traditional and interactive scores at one school

Step 3: Calculate the Differences

School A: 16 - 8 = 8 points difference

School B: 18 - 6 = 12 points difference ← Largest gap!

School C: 12 - 10 = 2 points difference

School D: 20 - 12 = 8 points difference

Step 4: Evaluate Each Choice

Option A: School C (2-point difference)

❌ Analysis: This is the SMALLEST difference, not "particularly pronounced." Opposite of what we need.

Option B: School B (12-point difference)

✅ Analysis: Perfect! This shows the largest gap between methods (6 vs. 18 = 12-point difference), which demonstrates a "particularly pronounced" difference. The data explicitly supports the claim about a dramatic contrast.

Option C: School D (highest interactive score)

❌ Analysis: While School D has the highest interactive score (20 points), this doesn't address the DIFFERENCE between methods. The claim isn't about absolute scores—it's about the gap between traditional vs. interactive. School D's difference is only 8 points.

Option D: School A (both methods > 5 points)

❌ Analysis: This talks about both methods being successful (both > 5), which doesn't support the claim about a pronounced DIFFERENCE. It's showing similarity, not contrast.

Correct Answer: B

💡 Key Lesson: "Particularly pronounced" signals looking for extremes. Calculate differences between compared values when the claim emphasizes contrast or disparity. Don't be distracted by high absolute values (Option C) when the question is about relative differences.

Quick Example: Line Graph

Scenario:

Climate scientist Dr. Sarah Martinez tracked atmospheric carbon dioxide (CO₂) levels over a 50-year period. Her data showed steady increases with occasional plateaus.

Atmospheric CO₂ Levels (parts per million)
325 ppm
338 ppm
354 ppm
369 ppm
389 ppm
412 ppm

Martinez noted that while CO₂ levels have risen consistently over the half-century, the rate of increase accelerated in recent decades. For example, from _______ atmospheric CO₂ increased by 23 ppm, demonstrating one of the most rapid decade-long increases in the dataset.

Question:

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

A) 1970 to 1980

B) 1990 to 2000

C) 2000 to 2010

D) 2010 to 2020

Quick Analysis:

What I need: The decade with a 23 ppm increase

Quick calculation:
A) 1970–1980: 338 - 325 = 13 ppm
B) 1990–2000: 369 - 354 = 15 ppm
C) 2000–2010: 389 - 369 = 20 ppm
D) 2010–2020: 412 - 389 = 23 ppm ✓

Answer: D (2010 to 2020)

This is straightforward once you calculate each decade's change. The claim explicitly states "23 ppm," so you just need to find which period matches. Option D shows exactly 23 ppm, confirming it's the "most rapid decade-long increase."

Additional Practice Examples

Practice Example 1: Data Table

Marine biologist Dr. Chen investigated coral reef biodiversity at various ocean depths. She documented the number of fish species observed at four depth ranges in the same geographic region.

Depth Range	Fish Species Count
0-10 meters	127
10-20 meters	143
20-30 meters	98
30-40 meters	64

Dr. Chen concluded that biodiversity peaked at moderate depths where sunlight and nutrients are optimal. Specifically, the depth range with the highest species diversity was _______

A) 0-10 meters, with 127 species observed.

B) 10-20 meters, with 143 species observed.

C) 20-30 meters, where species count began to decline.

D) 30-40 meters, the deepest range studied.

Answer: B

Explanation: The claim states the range with "highest species diversity." Looking at the table, 10-20 meters has 143 species—the maximum value. Option A (127) is close but not the highest. Option C mentions decline without stating the count (98), and Option D cites depth characteristic rather than biodiversity data. Always choose the data point that directly proves the superlative claim ("highest," "most," "greatest").

Practice Example 2: Comparative Analysis

Economists studied the relationship between education spending per student and literacy rates across five countries. While all countries showed positive correlations, the strength of this relationship varied.

Education Spending vs. Literacy Rates (2023)
Country A: $8,000/student → 94% literacy
Country B: $12,000/student → 97% literacy
Country C: $6,000/student → 89% literacy
Country D: $15,000/student → 99% literacy
Country E: $4,000/student → 98% literacy

The researchers noted that while higher spending generally correlated with higher literacy, one country achieved exceptional results despite below-average investment. Specifically, _______

A) Country D spent $15,000 per student and achieved 99% literacy.

B) Country C spent $6,000 per student and had 89% literacy.

C) Country E spent only $4,000 per student but achieved 98% literacy.

D) Country B spent $12,000 per student and reached 97% literacy.

Answer: C

Explanation: The claim highlights "exceptional results despite below-average investment"—an outlier that defies the general trend. Country E has the LOWEST spending ($4,000) but the SECOND-HIGHEST literacy rate (98%), showing efficiency. Option A shows high spending with high literacy (expected, not exceptional). Option B shows low spending with low literacy (also expected). Option D is average on both metrics. Country E breaks the pattern, making it the correct answer.

Practice Example 3: Identifying Trends

A technology analyst tracked smartphone adoption rates in rural communities over a six-year period, measuring the percentage of households with at least one smartphone.

Smartphone Adoption in Rural Areas (%)
34%
42%
51%
58%
63%
67%

The analyst observed that adoption accelerated during the COVID-19 pandemic as remote work and online learning became essential. The data shows that from _______

A) 2018 to 2020, adoption increased by 17 percentage points.

B) 2019 to 2020, adoption increased by 9 percentage points, the largest single-year gain in the dataset.

C) 2020 to 2023, adoption increased steadily to 67%.

D) 2022 to 2023, adoption increased by 4 percentage points.

Answer: B

Explanation: The claim mentions adoption "accelerated during the COVID-19 pandemic" (2020-2021). Let's check year-over-year changes: 2018→2019: +8%, 2019→2020: +9%, 2020→2021: +7%, 2021→2022: +5%, 2022→2023: +4%. The largest single-year jump is 2019 to 2020 (+9 percentage points), which aligns with early pandemic period. Option B correctly identifies this as the "largest single-year gain," supporting the acceleration claim. Other options cite accurate data but don't emphasize the dramatic change during pandemic onset.

Key Takeaways

Read the "story": Data visualizations tell narratives about trends, comparisons, or changes—identify what story the passage emphasizes
Check scales carefully: Misreading axis intervals is the #1 cause of wrong answers on quantitative questions
Match claim types: Superlatives ("most," "highest") need extreme values; comparisons need differences; trends need changes over time
Calculate when necessary: Sometimes you need to subtract values to find differences or changes not explicitly shown
Eliminate wrong data: Accurate but irrelevant data is a common trap—the right answer must support the SPECIFIC claim
Units matter: Pay attention to whether data is in percentages, thousands, millions, or other units
Don't overthink: Most questions require simple data reading or basic arithmetic—complex calculations usually mean you're on the wrong track
Verify before selecting: Double-check that your chosen answer accurately reflects what the graph shows
Time efficiently: Spend 60-90 seconds max on these questions—they're often quicker than textual evidence questions

Study Strategy & Resources

📊 Build Graph Reading Skills

Practice with real-world graphs from news articles
Study infographics on scientific topics
Complete data interpretation exercises daily
Learn to identify misleading graph presentations

🎯 Targeted Practice

Focus on official SAT practice tests
Review both correct AND incorrect answer explanations
Time yourself: 60-90 seconds per question
Practice with various graph types (bar, line, table)

📈 Master Common Patterns

Learn vocabulary: "correlation," "trend," "outlier," "peak"
Understand percentage vs. absolute change
Practice calculating differences and ratios
Recognize when data contradicts intuition

🔗 Related Skills

Command of Evidence: Textual
Central Ideas and Details
Inferences
SAT Math: Problem Solving & Data Analysis

🎓 NUM8ERS Expert Coaching

At NUM8ERS in Dubai, our SAT specialists teach students systematic approaches to quantitative evidence questions through hands-on practice with real SAT data visualizations. We focus on building both graph-reading skills and strategic thinking for evidence selection.

Our comprehensive program includes: Visual literacy training, pattern recognition drills, timed practice with adaptive feedback, and personalized error analysis. NUM8ERS students consistently achieve 700+ scores on Reading & Writing by mastering these data interpretation skills alongside textual analysis.

Textual vs. Quantitative Evidence: Quick Comparison

Feature	Textual Evidence	Quantitative Evidence
Evidence Source	Quotations from passage text	Data from graphs, charts, or tables
Skills Required	Reading comprehension, identifying explicit statements	Data interpretation, basic calculations, pattern recognition
Passage Types	Literary, scientific, historical, social science	Primarily scientific and social science research
Common Mistakes	Choosing vague/partial quotes; making assumptions	Misreading scales; citing irrelevant data
Time Investment	60-90 seconds (more reading required)	60-90 seconds (quicker with practice)
Best Strategy	Paraphrase claim, find explicit matching quote	Identify story data tells, match to claim type

💡 Pro Tip: Master BOTH evidence types! Quantitative questions may seem intimidating at first, but they're often easier to answer correctly once you understand graph reading. Many students find them faster than textual evidence questions because data is more objective than interpreting prose.