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Common Core ELAGrades 9–10Reading: Informational

RI.9-10.1: Cite Strong and Thorough Evidence

Also written as CCSS.ELA-LITERACY.RI.9-10.1 · Cluster: Key Ideas and Details.

All 41 Grades 9–10 ELA Standards

The Official Wording

Cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text.

Common Core State Standards, Grades 9-10, Reading: Informational Text · Read it at the source · Checked October 14, 2026

What RI.9-10.1 Means in Plain English

Ninth and tenth graders back a claim about an article or speech with strong and thorough evidence, enough to cover every part of it. Explaining a lost Mars probe takes one quote for the cause the text states and several for the failure it only implies.

Eighth grade (RI.8.1) asked for the single strongest piece of evidence, so students learned to rank quotes. Ninth and tenth grade ask whether the evidence, taken together, is enough. In eleventh and twelfth grade (RI.11-12.1) students also show where the text leaves matters uncertain.

RI.9-10.1 I Can Statements

  • I can support each part of my claim with evidence.
  • I can tell what a text states from what it implies.
  • I can gather several details that together prove an inference.

RI.9-10.1 Worked Example

The passage states one cause outright and implies a second, and the weak answer quotes only the first.

Read the Story
On September 23, 1999, NASA’s Mars Climate Orbiter fired its engine to slip into orbit around Mars, passed behind the planet as planned and was never heard from again.Investigators traced the loss to one file of ground software. A program written by the spacecraft’s builder, Lockheed Martin, reported the push from small thruster firings in pound-force seconds, an English unit. NASA’s navigation software read those numbers as newton-seconds, the metric unit the mission’s rules required. Each figure was off by a factor of about 4.45.The error was tiny on any single day, but it built up over nine months of travel. The craft arrived only about 57 kilometers above the surface, far deeper in the atmosphere than planned, and was most likely destroyed.During the cruise, navigators noticed that the craft’s path kept drifting from their predictions. Their concerns were discussed, but the mismatch was never resolved, and an optional last course correction was not made.The investigation board blamed more than the unit mix-up. It cited weak communication between the teams and a review process that never caught the mismatch.
A short passage written for this page.
Question: What does the passage say caused the loss of the orbiter, and what can you infer about whether the unit mix-up alone explains it? Support both parts with strong and thorough evidence.
Not Yet“The orbiter crashed because of a math mistake. The text says, ‘Each figure was off by a factor of about 4.45.’”It answers only the first half, with one quote that shows how big the error was, not how it happened or why nobody caught it. Calling it a math mistake also misreads the text: the numbers were right, but they were read in the wrong unit.
Meets the Standard“The passage states the direct cause: Lockheed Martin’s software reported thruster data ‘in pound-force seconds,’ and NASA’s software ‘read those numbers as newton-seconds.’ It also leads me to infer that the unit error alone did not doom the craft. The failure to catch it did. Because the error ‘built up over nine months of travel,’ there was time to find it. Navigators saw the path ‘kept drifting from their predictions,’ yet ‘an optional last course correction was not made.’ Finally, the board ‘blamed more than the unit mix-up,’ pointing to weak communication and review. Together these show a warning that was noticed and never acted on.”It separates what the text states from what it implies, and backs the inference with evidence for every part of it: the time available, the warning sign, the missed chance and the board’s finding.
Question Stems to Use
What does the text state outright about the cause? Quote it.What does the text suggest without saying it? Which details led you there?Does your evidence cover every part of your claim, or only one part?Which detail would a doubtful reader ask you to explain? Address it.What happens to your inference if you remove this quote?

Common Mistakes with RI.9-10.1

Stopping at the stated cause

“The orbiter was lost because of the unit mix-up,” and the answer ends there

Try this: Ask students for two claims every time, one the text states and one it implies, each with its own evidence.

One quote for a claim with several parts

A single line about the 4.45 factor offered as proof that nobody caught the error

Try this: Have students split the claim into parts, then check that each part has at least one quotation behind it before drafting.

An inference with nothing under it

“Maybe someone should have noticed,” with no quotation to back it

Try this: Require every inference to cite at least two details that point the same way, then say in one sentence what links them.

Where RI.9-10.1 Fits

Comes BeforeRI.8.1Cite the evidence that most strongly supports an analysis of what a text says and implies.
AlongsideRL.9-10.1The same strong, thorough evidence for novels, plays and poems.RST.9-10.1Cite precise details of explanations and descriptions in science and technical texts.
Comes NextRI.11-12.1Add where the text leaves matters uncertain to a strong, thorough analysis.

Practice RI.9-10.1

Quick Check

  1. What does the passage state caused the loss of the orbiter?
  2. What can you infer about why the unit error was never fixed?
  3. Why is “Each figure was off by a factor of about 4.45” not enough evidence for that inference?

RI.9-10.1: Other Names

RI.9-10.1CCSS.ELA-LITERACY.RI.9-10.1

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.