Can You Cite a Study That You Know Only Through Another Paper?

Another Paper Describes the Study You Need. Can You Cite the Original?

You are reading a journal article and encounter a sentence describing an earlier study that seems highly relevant to your own work. The authors summarize what the earlier researchers supposedly found and provide the original citation in their reference list.

You have not read that original study.

Can you simply copy its citation into your own paper and cite it for the finding?

Usually, you should first try to obtain and read the original. If that is not reasonably possible, citation styles provide mechanisms for acknowledging that your knowledge of the original came through another source. What you should avoid is making the citation look as though you personally examined evidence that you actually know only through someone else's description.

Do Not Turn Someone Else's Reading Into Your Own

Why Following the Citation Back to the Original Matters

First, identify what you actually consulted

Suppose Paper B states that an earlier study, Paper A, found that a particular teaching intervention improved student performance.

You read Paper B. You did not read Paper A.

Your immediate source of information about Paper A is therefore Paper B. Paper A may be the original source of the reported finding, but you know that finding only through another author's representation of it.

This distinction is easy to lose when reference-management software makes adding a perfectly formatted citation take a few seconds. Bibliographic completeness, alas, is not evidence that anyone actually opened the paper.

Why not simply copy the original reference?

Because doing so can imply a stronger evidential relationship than you actually have.

If you cite Paper A normally, readers will usually have no reason to suspect that you never examined it. They may reasonably assume that your description of Paper A comes from your reading of Paper A.

But your description may actually be Paper B's interpretation.

That matters because Paper B may have compressed the original finding, omitted a qualification, described only one analysis, generalized beyond the original sample, or made an error in its citation or interpretation. Even when Paper B is careful and accurate, you have not independently established that accuracy until you consult Paper A.

A later author's summary is an interpretation, not a transparent window

Scholarly writing necessarily involves selection. Authors cite earlier work for particular purposes. They may devote one sentence to a study that contains twenty pages of methods, results, qualifications, and discussion.

Consider a later paper that says:

"Previous research found that online collaborative learning improved academic performance."

The original study might reveal that the effect appeared only for one outcome, only after adjustment, only among a particular subgroup, or only in comparison with a specific control condition. It might also have used an observational design that does not support the causal wording used by the later author.

Until you inspect the original, you cannot know how much nuance disappeared during transmission.

The reference itself may contain an error

Another reason to follow citations backward is surprisingly mundane: reference lists can be wrong.

An author name may be misspelled. The publication year can be incorrect. The title may contain an error. A DOI can be mistyped. Page numbers can point to the wrong article. References copied through generations of papers can perpetuate mistakes.

If you copy Paper A's reference directly from Paper B without verifying it, you may reproduce the error.

When possible, verify the original bibliographic record through the publisher, DOI record, scholarly database, journal archive, or another authoritative source rather than treating another paper's reference list as definitive metadata.

Reading the original lets you judge whether it supports your claim

A citation should support the sentence to which it is attached. That sounds obvious, but secondary transmission makes the relationship surprisingly easy to weaken.

When you obtain Paper A, ask:

• Did the study actually investigate the question for which I am citing it?
• Did it report the finding attributed to it?
• Was the population or context accurately represented?
• Does the design support the type of claim I want to make?
• Were important qualifications omitted in the later paper?
• Has the original subsequently been corrected or retracted?

You may discover that the study is still useful but supports a narrower statement than Paper B led you to expect.

Try to obtain the original before resorting to secondary citation

Major citation systems generally favor consulting original sources when possible. MLA's guidance on indirect sources provides a mechanism for acknowledging material encountered through another work, while Chicago explicitly discourages citation through a secondary source when the original can be examined. APA guidance likewise treats secondary citation as something to use sparingly when the original is unavailable.

That preference is not mere citation etiquette. It protects the chain of evidence.

If you already have the citation but not the article, work through the available routes for finding the full text from a bibliographic reference. Search the DOI, exact title, publisher record, scholarly databases, institutional access, and library services.

A paywall is not enough reason to stop looking

If the original leads to a publisher paywall, that does not necessarily mean you must use a secondary citation.

Check your institutional library. Search for a legitimate open-access version of the paper. An accepted manuscript may be available in an institutional or disciplinary repository even when the publisher's version remains inaccessible.

You can also request a copy directly from the author or ask your library about document delivery or interlibrary loan.

The more important the original study is to your argument, the stronger the reason to make a serious retrieval effort.

When might secondary citation be reasonable?

Sometimes the original genuinely cannot be consulted. It may be out of print, unavailable through accessible collections, undigitized, written in a form you cannot obtain, or otherwise beyond reasonable retrieval despite a serious attempt.

In those circumstances, a secondary citation can preserve useful information while making its provenance explicit.

Chicago's guidance states that citing a source through another source is generally discouraged because authors are expected to examine the works they cite, but it permits the practice when the original is unavailable. MLA provides an explicit qtd. in convention for indirect sources. APA uses an as cited in construction for a source known through another source.

The exact formatting differs, so the detailed question of when secondary citation is acceptable and how it works should be handled according to the citation style you are required to use.

Secondary citation should reveal the chain, not hide it

The basic logic is:

Original study → source you actually read → your paper

Your citation should not erase the middle step.

In APA-style author-date writing, for example, a secondary citation identifies the original source and then uses "as cited in" to identify the source actually consulted. Only the secondary source that was actually read is normally included in the reference list under APA's secondary-source convention.

MLA uses qtd. in for an indirect quotation and includes the work actually consulted in Works Cited. Chicago's notes approach can identify the original followed by "quoted in" and the secondary source. The exact bibliography treatment depends on the Chicago system and edition being followed.

Paraphrasing does not remove the secondary-source problem

Researchers sometimes assume that secondary citation matters only for direct quotations. It does not.

Suppose Paper B paraphrases Paper A, and you paraphrase Paper B's description of Paper A. You still have not read Paper A. Changing the wording does not change the provenance of the information.

MLA explicitly addresses indirect paraphrasing as well as indirect quotation. If you paraphrase information attributed to a source you did not consult, the intermediary remains relevant because it is the source through which you obtained the information.

The underlying principle is straightforward: citation provenance follows information, not quotation marks.

Be careful when the secondary source makes a stronger claim than the original may support

Secondary transmission can amplify claims.

Paper A might report an association. Paper B describes it as an effect. Paper C cites Paper B and calls it evidence of causation. By the time Paper D repeats the claim, the original design may have disappeared entirely from view.

Reading the original interrupts that chain.

This is particularly important when the claim concerns causality, effectiveness, prevalence, risk, diagnostic accuracy, policy outcomes, or other conclusions where methodological details substantially affect interpretation.

Do not use a secondary citation to borrow authority you have not checked

Sometimes an older or famous source appears repeatedly in the literature. It can become tempting to cite it because everyone else does.

If you have not read it, however, you do not know whether it actually supports the proposition for which it has become conventionally cited.

This phenomenon can create citation chains in which later authors cite earlier authors without returning to the underlying work. Errors and oversimplifications can then propagate through the literature.

If the source is important enough to lend authority to your argument, it is usually important enough to try to retrieve.

What if you can access only the original abstract?

This creates a slightly different situation.

If you personally read the original abstract, then you have directly consulted part of the original publication record. You may be able to cite the paper for a limited claim explicitly supported by that abstract. But you still should not treat yourself as having examined details available only in the full article.

The question then becomes whether the abstract itself provides enough evidence for the claim you want to make, rather than whether your knowledge comes entirely through another paper.

What if Paper B merely points you to Paper A?

That is not a problem if you then obtain Paper A and read it yourself.

Scholars routinely discover relevant literature through the reference lists of other papers. Citation chaining is a normal and useful search technique.

Once you locate and consult the original, you can cite it directly for claims you verified there. You do not need to cite Paper B merely because it helped you discover Paper A, unless Paper B itself contributes something relevant to your argument.

The problem arises only when discovery is mistaken for consultation.

Following a Secondary Claim Back to the Original Study

If the original had remained genuinely inaccessible, you could instead have considered a transparent secondary citation. What would not be defensible is reproducing the review's interpretation while making the citation look like your own reading of the original.

Common Mistakes When Citing Studies Found Through Other Papers

Follow Important Claims Backward Until You Reach Evidence You Can Actually Examine

A reference list is not merely a supply of citations to transfer into your own manuscript. It is also a map for locating evidence.

When another paper points you toward an important study, use that citation as a retrieval lead first. Decide how to cite it only after you know whether you can consult the original.

This last option is sometimes overlooked. Not every interesting statement encountered in the literature needs to survive into your manuscript. Occasionally the cleanest citation problem is the sentence you discover you did not need in the first place.

Before Citing a Study You Found Through Another Paper, Check These Points

Questions About Citing Research Through Another Source

Cite the Evidence You Actually Examined

How to Cite This Guide

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