Write an explanation organized into categories with headings, a table and precise vocabulary

Learning goal: Write informative/explanatory texts that examine a topic and convey ideas, concepts and information through the selection, organization and analysis of relevant content. Establish a clear thesis statement to present information; introduce the topic and preview what follows; organize ideas into broader categories with headings and a graphic where they aid comprehension; develop the topic with relevant, well-chosen facts, definitions, concrete details and examples; use varied transitions; use precise language and domain-specific vocabulary; keep a formal style; and conclude in a way that follows from the explanation.

Explanation is not argument. An argument asks the reader to accept a disputable position. An explanation asks the reader to understand something: how a process works, what a set of numbers means, how ideas relate. The two use some of the same tools (thesis, evidence, transitions, conclusion), but the thesis of an explanation presents information rather than a side. "Ridgeview should build the classroom" is an argument thesis. "A volunteer survey can show what its respondents preferred, but not what the whole school prefers" is an explanatory thesis: it states the understanding the text will build, and a reader on either side of the courtyard question can accept it.

Establish a clear thesis statement to present information. The thesis should name the topic and the central concept the reader will take away. Write it before you draft, because it is the test for every later sentence: does this sentence help the reader understand the thesis, or is it here because it is interesting? Selection of relevant content means keeping the first kind and cutting the second.

Introduce the topic and preview what is to follow; organize into broader categories. A grade 8 explanation of any length benefits from categories: the writer groups related information under a small number of headings, and the introduction previews them. The model below uses four categories, each a heading: what the survey asked, who answered, what the numbers show and what the numbers cannot show. The categories are broader than any single fact; each holds several facts that belong together. A reader can find the answer to "how many responded?" without rereading the whole text, which is what formatting is for. Headings are not decoration; in a text of this length, a heading with one sentence under it usually marks a category too small to stand alone, and the model merges such a heading with a neighbor.

Include graphics and multimedia when they aid comprehension. A table is the right graphic when the reader must compare several numbers. The table in this lesson shows the three survey options with counts and percentages, and the prose refers to it ("Table 1 shows..."). A chart, diagram or short video belongs in an explanation only if it makes something clearer than the sentences alone would. A graphic without a caption, units and a reference in the text is an interruption, not an aid.

Develop the topic with relevant, well-chosen facts, definitions, concrete details, quotations and examples. Development is what separates an explanation from a list. A fact (212 students responded) becomes understanding when it is placed next to a definition (response rate: the share of the people asked who answered), a computation (212 of 480 is 44 percent) and an example of why that matters (if the 268 nonrespondents leaned toward the garden, the whole-school result could differ). Quotations from a source are appropriate when the wording itself carries information, as when the survey's exact question is quoted so the reader can judge what it measured.

Use appropriate and varied transitions. Explanations rely on transitions that show relationships among ideas and concepts: in other words (restatement), for instance (example), as a result (consequence), by contrast (difference), specifically (narrowing), in the same way (similarity). Varied means the writer chooses the transition that names the actual relationship rather than opening every paragraph with also. If two paragraphs are related by contrast, by contrast tells the reader so before the paragraph begins.

Use precise language and domain-specific vocabulary. Every field has words that say in one term what would otherwise take a sentence. In survey work those include population (everyone the question is about), sample (the people selected to be asked; when everyone is invited, as in the council's survey, the useful distinction is between those asked and those who answered), respondent (a person who answered), response rate, self-selected (a sample whose members chose to take part), nonresponse (the failure to obtain answers from some of the people asked) and nonrespondents (the people asked who did not answer). Introduce each term at first use with a short definition, then use it consistently. Precise language also means the exact verb: the survey recorded preferences; it did not prove anything about the school.

Establish and maintain a formal style. Same rule as the argument: specific nouns, no slang, no intensifiers, and a tone that informs rather than sells. "The survey is super unreliable" is informal and also imprecise; "the survey's self-selected sample limits what it can show about the whole school" is formal and says exactly what the limit is.

Provide a concluding statement or section that follows from the information presented. The conclusion restates the thesis in light of the categories and may say what a reader should do with the understanding: here, how to read any volunteer survey. It does not introduce a new topic.

Original model explanation — Reading a Volunteer Survey.

Introduction. In spring, Ridgeview's student council asked students which courtyard project they preferred. The results, 58 percent for an outdoor classroom, were quoted in both proposals. This explanation examines what that figure means. A volunteer survey can show what its respondents preferred, but not what the whole school prefers, and the difference depends on who answered. The sections below describe what the survey asked, who answered, what the numbers show and what they cannot show.

What the survey asked. The council posted one question in every homeroom: "Which project should the school build in the courtyard: an outdoor classroom, a garden, or no preference?" The question offered three fixed options and no space for a different idea. In other words, a student who wanted both, or neither, had to choose "no preference" or not answer.

Who answered. Ridgeview enrolls 480 students. Of these, 212 completed the survey. The response rate, the share of the people asked who answered, was therefore 212 divided by 480, about 44 percent. Because students decided for themselves whether to fill in the form, the sample is self-selected. The 268 students who did not respond are the nonrespondents, and the survey records nothing about them.

What the numbers show. Table 1 lists the results. Of the 212 respondents, 123 chose the outdoor classroom, 66 chose the garden and 23 chose no preference. As percentages of the respondents, these are 58, 31 and 11. Specifically, among students who answered, the classroom was preferred by nearly two to one over the garden.

What the numbers cannot show. The 58 percent is a fact about the 212 respondents, not about the 480 students. If the nonrespondents resembled the respondents, the whole-school result would be similar; if, for instance, students in the seventh-grade science sections that would use the garden were less likely to see the homeroom posting, the whole-school result could be closer. The survey cannot decide between these possibilities, because it collected nothing from the 268 nonrespondents. By contrast, a survey that recorded every student's answer, or a random sample that did not depend on volunteering, could support a claim about the school.

Conclusion. The student council survey shows a clear preference for the outdoor classroom among the students who answered it, and a reader should quote it that way: 123 of 212 respondents, or 58 percent of a self-selected sample with a 44 percent response rate. It does not show that 58 percent of Ridgeview prefers the classroom. Reading any volunteer survey means asking the same two questions, who was asked and who answered, before deciding what the percentage is a percentage of.

Worked selection of relevant content: A draft of the model included this sentence under "Who answered": "The council's president, Maya, designed the poster in green because green is the school color." The detail is true in the scenario and concrete, but it does not help a reader understand who answered or what the result means. Selection means cutting it. The sentence that replaced it, "Because students decided for themselves whether to fill in the form, the sample is self-selected," adds a definition and a fact the thesis depends on. Relevant content is content the thesis needs.

Worked computation inside an explanation: The response rate is 212 divided by 480. Divide: 212 ÷ 480 = 0.4417, which rounds to 44 percent. The percentages in Table 1 are each count divided by 212, not by 480: 123 ÷ 212 = 0.580 (58 percent); 66 ÷ 212 = 0.311 (31 percent); 23 ÷ 212 = 0.108 (11 percent). The three round to 100 together. A common error is to divide 123 by 480, which gives 26 percent and describes a different quantity: the share of all enrolled students who both answered and chose the classroom. The explanation must say which denominator it is using, and the table's column heading does that.

Worked transition choice: Between the "What the numbers show" and "What the numbers cannot show" sections, the draft used Also. The relationship between the sections is contrast (what is known versus what is not), so By contrast or a sentence such as "The same numbers have a limit" names the relationship correctly. Inside a section, for instance introduces the seventh-grade example and specifically narrows from the three counts to the two-to-one comparison. Each transition was chosen for the relationship it names.

Worked heading test: A draft heading "Green posters" had one sentence under it and was merged into "What the survey asked," where the posting method belongs; the poster's color itself was cut, as the worked selection shows. A heading earns its place when several related facts sit under it and a reader would look for them there.

Planning and table task: Choose an explainable topic from this unit or from a process you have directly observed (how your school schedules lunch periods, how a club elects officers, how a recycling pickup works). Write an explanatory thesis in one sentence. List three to five broader categories as headings and place at least two facts, one definition and one concrete example under each. Design one table or chart with a title, labeled columns, units and a caption, and write the sentence in your text that will refer to it. Mark every number with the source it came from; if you have no source, the number does not go in.

Independent performance: Write a 450-word explanation with an introduction that states the thesis and previews the categories; three or more headed sections; at least three domain-specific terms, each defined at first use and then used consistently; one referenced table or graphic with caption; varied transitions chosen for the relationships they name; formal style; and a conclusion that follows from the information and tells the reader what to do with it. Have a partner read only your headings and table and predict what each section says; where the prediction fails, revise the heading or the section. Check every percentage by stating its denominator.