Common Core LiteracyGrades 9–10History & Social Studies

RH.9-10.2: Central Ideas and How They Develop

Also written as CCSS.ELA-LITERACY.RH.9-10.2 · Cluster: Key Ideas and Details.

The Official Wording

Determine the central ideas or information of a primary or secondary source; provide an accurate summary of how key events or ideas develop over the course of the text.

Common Core State Standards, Grades 9-10, Reading: History & Social Studies · Read it at the source · Checked October 14, 2026

What RH.9-10.2 Means in Plain English

Ninth and tenth graders find the main idea of a speech, diary or history chapter and summarize how its key events build that idea from the opening to the end. An account of rural mail delivery grows from one saved trip to town into farms tied to the nation.

Middle school (RH.6-8.2) asked for a summary kept free of students’ own knowledge and opinions. Ninth and tenth grade add how the ideas develop across the text. In eleventh and twelfth grade (RH.11-12.2), the summary must make the relationships among key details and ideas clear.

RH.9-10.2 I Can Statements

I can state a source’s central idea as a full claim.
I can trace how a central idea develops across a text.
I can summarize key events in order without adding my opinions.

RH.9-10.2 Worked Example

The account starts with one saved trip to town and ends with farms tied to the nation, and the weak answer misses the widening in between.

Read the Story

Until the 1890s, a farm family that wanted its mail had to go and get it. City dwellers had enjoyed free delivery to their doors since 1863, but farmers, though most Americans still lived in the countryside, drove a wagon to a post office in town and often went a week or more without news.In 1896 the Post Office tried an experiment: carriers in West Virginia began bringing mail to boxes at farm gates along three rural routes. Farmers elsewhere flooded their representatives with petitions for routes of their own, and in 1902 Rural Free Delivery became permanent.The service came with a condition. Carriers would not run a route through impassable mud, so counties that wanted delivery graded and graveled their roads, and the mail carrier became an argument for good roads.Once the mail came daily, so did the outside world. Farm families read daily newspapers, followed crop prices and ordered from mail-order catalogs. When parcel post began in 1913, the carrier brought packages too, and small-town merchants protested that the catalog companies were stealing their customers.Rural Free Delivery began as a convenience. Within two decades it had tied the farm to the nation’s markets, roads and news.

A short passage written for this page.

Question: What is the central idea of the passage, and how does it develop from the first paragraph to the last? Write an accurate summary.

Not Yet“The passage is about the mail. Farmers got mail delivered starting in 1896, roads got better, and there were catalogs and newspapers.”It names a topic, not a central idea, and lists events without connecting them. It never says why the roads improved or how the effect keeps widening, so the summary has the facts but not the development.

Meets the Standard“The central idea is that free rural mail delivery did far more than save farmers a trip to town: it pulled isolated farm families into the life of the nation. The passage builds that idea in widening steps. It opens with the isolation, farmers who ‘went a week or more without news’ while cities had delivery. It then shows the 1896 experiment spreading through farmers’ petitions until it ‘became permanent’ in 1902. Next the effect reaches the roads, because counties improved them to qualify for routes. Then it reaches markets and news: daily papers, crop prices, catalogs and, after 1913, parcel post. The last paragraph names the change outright, a ‘convenience’ that ‘tied the farm to the nation’s markets, roads and news.’”It states the central idea as a claim, then summarizes in order how each paragraph widens it, using the passage’s own facts and adding no opinions.

Question Stems to Use

What is the passage about? Now, what does it say about that topic?Where does the first paragraph start, and where does the last one end up?How does each paragraph widen or change the idea before it?Which sentence states the central idea most directly?Does your summary add anything the text does not say?

Common Mistakes with RH.9-10.2

A topic instead of a central idea

“The passage is about the mail.”

Try this: Ask students to finish the sentence “The passage shows that rural mail delivery…” so the answer has to make a claim.

A list of events with no development

“There were petitions, then roads, then catalogs, then parcel post.”

Try this: Have students write one sentence per paragraph saying how it widens or changes the idea before it, then join them.

Opinions slipping into the summary

“Rural mail was a great idea, and farmers must have loved it.”

Try this: Cross out every phrase in the summary that the passage does not state or directly support, then reread it aloud.

Where RH.9-10.2 Fits

Comes BeforeRH.6-8.2Summarize a primary or secondary source accurately, apart from prior knowledge or opinions.

AlongsideRI.9-10.2Trace how a central idea emerges and is shaped and refined by specific details.WHST.9-10.2Write an explanation of a historical event with a clear focus and a conclusion.

Comes NextRH.11-12.2Summarize so that the relationships among key details and ideas are clear.

Practice RH.9-10.2

Quick Check

Why did counties grade and gravel their roads?
Carriers would not run a route through impassable mud, so counties improved their roads to get delivery.
What changed for farm families when parcel post began in 1913?
Carriers brought packages too, so catalog orders came to the farm, and small-town merchants protested about losing customers.
What is the central idea of the passage?
Free rural mail delivery began as a convenience and ended up tying farm families to the nation’s markets, roads and news.

RH.9-10.2: Other Names

RH.9-10.2CCSS.ELA-LITERACY.RH.9-10.2