何を引用すべきか? APA・MLA・Chicagoにおける一般常識

一般常識（引用しない）

Widely known scientific and historical facts—such as the molecular structure of water (H2O), or that Andrew Jackson was the seventh president of the United States—generally count as common knowledge.

統計（必ず引用）

The U.S. population reached 340.1 million, up 0.98% from 336.8 million on July 1, 2023 — the highest year-over-year increase since a jump of 0.99% between 2000 and 2001.

誰かの解釈（必ず引用）

If you read in R.A.C. Parker’s history of World War II that British Prime Minister Neville Chamberlain did not have to agree to the 1938 Munich Pact with Hitler, and that he could have chosen an alternate path, you would need to acknowledge the source, since this judgment is Parker’s theory rather than a widely agreed upon fact.

録画されていない講義（APA 7 §8.9、本文中のみ）

(T. Nguyen, personal communication, February 24, 2020)

Cite the work of those individuals whose ideas, theories, or research have directly influenced your work.

In addition to crediting the ideas of others that you used to develop your thesis, provide documentation for all facts and figures that are not common knowledge.

Both paraphrases (see Sections 8.23-8.24) and direct quotations (see Sections 8.25-8.35) require citations.

Avoid both undercitation and overcitation. Undercitation can lead to plagiarism (see Section 8.2) and/or self-plagiarism (see Section 8.3).

The only source material that you can use in an essay without attribution is material that is considered common knowledge and is therefore not attributable to one source.

Common knowledge is information generally known to an educated reader, such as widely known facts and dates, and, more rarely, ideas or language.

Facts, ideas, and language that are distinct and unique products of a particular individual's work do not count as common knowledge and must always be cited.

Common knowledge includes information widely available in reference works, such as basic biographical facts about prominent persons and the dates and circumstances of major historical events.

You should footnote information that you borrow from someone else that isn’t common knowledge, whether you quote it or not; and if any of the information is disputed (for instance, if some sources say that Jefferson had seven sisters), it’s a good idea to footnote the version that supports your statement.

Everyone knows that George Washington was the first president, so even if you read it somewhere, there are so many sources that say so that it doesn’t make sense to give credit to a particular one.

It’s not always clear whether something should be cited or not, so until you develop some confidence, be generous in your citations, without being silly.

Broadly speaking, common knowledge refers to information that the average, educated reader would accept as reliable without having to look it up.

Did I know this information before I took this course?

Did this information/idea come from my own brain?

If you answer “no” to either or both of these questions, then the information is not “common knowledge” to you.

The moral of this handout: When in doubt, give a citation.

Always attribute every idea, fact, or finding you put in your paper when you write it.

Another common form of idea plagiarism is when students remember a fact they learned in class and put it in their paper without citing it or when they write about a fact they heard somewhere and mistakenly assume it is common knowledge.

Most important, always search the literature to find a source for any ideas, facts, or findings that you put in your paper.

A description of the symptoms of Asperger’s Syndrome would need to be cited for a composition in a general writing class but probably not need citation for an audience of graduate students in psychology.

A reference to the practice of fair value accounting would be understood by a group of economists, but would need citation to an audience of non-experts.

A statement reporting that 24% of children under the age of 18 live in households headed by single mothers would need to be cited. This is information that would not be known to the average reader, who would want to know where the figure was obtained.

APA 7、録画されていない講義（本文中のみ）:

(T. Nguyen, personal communication, February 24, 2020)

APA 7、叙述の personal communication:

E.-M. Paradis (personal communication, August 8, 2019)

APA 7、授業サイトに置かれたスライド（Common Reference Examples、2026年3月3日）:

Mack, R., & Spake, G. (2018). Citing open source images and formatting references for presentations [PowerPoint slides]. Canvas@FNU. https://fnu.onelogin.com/login

APA 7、スライドの本文中:

(Mack & Spake, 2018)

Chicago 18 の注（Quick Guide、録画されたオンライン講義）:

2. Eric Oliver, "Why So Many Americans Believe in So Many ‘Crazy’ Things," moderated by Andrew McCall, virtual lecture, February 23, 2022, posted March 21, 2022, by University of Chicago, YouTube, 1:01:45, https://youtu.be/hfq7AnCF5bg.

MLA 9 著作引用の型（対面の講義。実際の回を記入）:

Speaker Last, Speaker First. "Title of Lecture." Course or series, Day Mon. Year, Institution. Lecture.

参考文献（Census Bureau の記事）:

Wilder, K. (2024, December 19). New 2024 population estimates show nation’s population grew by about 1% to 340.1 million since 2023. U.S. Census Bureau. https://www.census.gov/library/stories/2024/12/population-estimates.html

括弧内:

The resident population reached 340.1 million on July 1, 2024 (Wilder, 2024).

参考文献（論文; Common Reference Examples、2026年3月3日）:

Niepel, C., Hausen, J. E., Weber, A. M., & Möller, J. (2025). Understanding mean-level and intraindividual variability in state academic self-concept: The role of students’ trait expectancies and values. Journal of Educational Psychology, 117(5), 772–788. https://doi.org/10.1037/edu0000946

叙述:

Niepel et al. (2025) measured both mean-level and within-person variability in state academic self-concept.

参考文献（Jack、Harvard の「所有された結論」の例）:

Jack, A. A. (2019). The privileged poor: How elite colleges are failing disadvantaged students. Harvard University Press.

著作全体の括弧内:

Jack’s conclusions about economically disadvantaged students at elite colleges need a citation (Jack, 2019).

著作引用（Census Bureau の記事）:

Wilder, Kristie. "New 2024 Population Estimates Show Nation’s Population Grew by About 1% to 340.1 Million Since 2023." U.S. Census Bureau, 19 Dec. 2024, www.census.gov/library/stories/2024/12/population-estimates.html.

括弧内（ページのないウェブ出典）:

The resident population reached 340.1 million on 1 July 2024 (Wilder).

著作引用（Jack）:

Jack, Anthony Abraham. The Privileged Poor: How Elite Colleges Are Failing Disadvantaged Students. Harvard UP, 2019.

著作全体の本文中:

The conclusions Jack drew from his study of economically disadvantaged students at elite colleges need a citation (Jack).

文:

Yu から取った文は、公式の初出注のページで引用します。¹

初出注（CMOS Quick Guide）:

1. Charles Yu, Interior Chinatown (Pantheon Books, 2020), 45.

短縮注:

3. Yu, Interior Chinatown, 48.

書誌（書籍）:

Yu, Charles. Interior Chinatown. Pantheon Books, 2020.

雑誌の事実の注（CMOS Quick Guide）:

1. Hyeyoung Kwon, "Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life," American Journal of Sociology 127, no. 6 (2022): 1842–43, https://doi.org/10.1086/720277.

国勢調査の統計の注:

4. Kristie Wilder, "New 2024 Population Estimates Show Nation’s Population Grew by About 1% to 340.1 Million Since 2023," U.S. Census Bureau, December 19, 2024, https://www.census.gov/library/stories/2024/12/population-estimates.html.

author-date の本文中（Quick Guide の形式）:

(Yu 2020, 45)

Overcitation can be distracting and is unnecessary. For example, it is considered overcitation to repeat the same citation in every sentence when the source and topic have not changed. Instead, when paraphrasing a key point in more than one sentence within a paragraph, cite the source in the first sentence in which it is relevant and do not repeat the citation in subsequent sentences as long as the source remains clear and unchanged (see Section 8.24).

• この論文を調べている間、この事実を特定の出典から学んだのではない。
• 想定する読者は、誰が言っているのか尋ねることなくそれを受け入れるだろう。
• 特定の著者の著作だけでなく、どの一般的な参考資料でも確認できる。
• それは解釈、推計、統計、理論ではなく、事実である。
• 文言はどれも借りていない。
• 講義、セミナー、会話から得たものではない。
• 上記のどれかが当てはまらない場合は、自分のスタイルの形式で引用を加えた。