GRE Data Interpretation:
read the data set before the questions

What is a Data Interpretation set?

In Quantitative Reasoning, ETS groups some questions into sets: all refer to the same table, chart, or other data display and ask you to interpret or analyze that data. Questions in a set may be multiple-choice with one or more answers, or numeric-entry. The question format can change; the data set stays the same.

Do not read too much into one point: the cited ETS pages do not specify the number of sets per section or questions per set. They state that a question is either independent or part of a set. The published structure has two Quant sections: twelve questions in twenty-one minutes, followed by fifteen in twenty-six minutes. For the shorter GRE, introduced on September 22, 2023, ETS states in its 2023 FAQs that the test covers the same content as before, and its Quant page still describes these sets. Prepare for the format, not a set quota.

What does a chart drawn to scale allow you to do?

ETS distinguishes between two kinds of figures. Geometry figures—lines, circles, triangles, and quadrilaterals—are not necessarily drawn to scale: you cannot judge a length or angle by eye. Coordinate systems and data displays—bar charts, pie charts, and curves—are drawn to scale, so you can read, estimate, or compare values by sight or measurement. For a data chart, visual inspection is allowed, unlike for geometry.

This guarantee applies to the scale shown, not necessarily to zero. ETS’s sample-question guide also warns about broken scales and bars that do not start at 0. Using this article’s data: if the Student visitor bars, 60 and 48 thousand, are plotted on an axis that starts at 40, they are 20 and 8 units high. The second appears two and a half times shorter than the first, although it is 80% of its value. Compare bar heights directly only when the axis is linear, starts at 0, and has no break; otherwise, read values from the scale.

In what order should you read a data set?

Scan the display instead of studying it cell by cell: ETS recommends identifying what it is about, then focusing only on what the questions ask. The protocol has seven steps (listed below), from the quickest to the most involved.

One rule applies to all these steps: answer using only the data, common facts (such as the number of days in a year), and your mathematical knowledge. Information you remember about the real-world context—a museum or a market—that cannot be derived from the data does not belong in your answer.

• Title: what the data set is about, the population, and the time period.
• Units: thousands, millions, counts, or percentages. ETS recommends checking the titles, labels, and legends.
• Scale and legend: intervals, where the axis starts, what the colors or patterns represent, and any notes clarifying the data.
• Question: reread what is being asked—a count, a share, a relative or absolute change—and the expected answer format.
• Targeted reading: note only the relevant cells or bars on your scratch paper, with their units.
• Estimate before calculating: round the data, predict the approximate value and direction of the answer. This often lets you eliminate choices before calculating.
• Plausibility check: correct unit, correct sign, and a value consistent with your estimate.

A fictional data set

The following three exercises use the same data set, created for this article: visitors to a fictional museum, in thousands, by ticket category. Apply the first steps before reading a question: check the title, units, and the fact that no total row is provided. Calculate the total when a question asks for a share or a change in the total number of visitors.

Exercise 1: a count is not a rate

Single-answer question. Before dividing, express each change as a fraction of its own base: you can often identify the largest fraction without calculating.

Exercise 2: shares, totals, and bases

Multiple-answer question: when no number is specified, select every true statement and no others. First calculate both totals, 300 and then 320; several statements depend on using the correct total or base.

Exercise 3: project a relative change

Numeric-entry question, with no answer choices to guide you. You must use the requested unit—thousands—and choose the right base: the 2024 value, not the 2023 value.

How can you check an answer before submitting it?

A few quick checks catch the errors described above. Shares for categories that make up the same total without overlap add up to 100%, allowing for rounding: 40, 20, about 13.3, 10, and 16.7% for 2023. A large discrepancy is a reason to check the total and categories used. A decrease gives a result below the starting value; an increase gives a higher one. A change in share is expressed in percentage points: Student’s share falls from 20% to 15%, a decrease of 5 points, or one-quarter in relative terms. Finally, answer in the unit requested: 38.4 if the question asks for thousands.

The on-screen calculator provided in Quant performs the operations you choose but does not check the base you used. In Numeric Entry, the button that transfers the calculator display to the answer box does not work for a fraction, and ETS asks for the exact value unless rounding is requested. There is no penalty for a wrong answer, so answer every question.