Fatally Flawed

Refuting the recent study on encyclopedic accuracy by the journal 

Nature

Encyclopædia Britannica, Inc.

March 2006

In its December 15, 2005, issue, the science journal 

Nature

published an article that claimed to

compare the accuracy of the online 

Encyclopædia Britannica

with 

Wikipedia

, the Internet database

that allows anyone, regardless of knowledge or qualifications, to write and edit articles on any sub-
ject.

1

Wikipedia

had recently received attention for its alleged inaccuracies,

2

but 

Nature

’s article

claimed to have found that “such high-profile examples [of major errors in 

Wikipedia

] are the excep-

tion rather than the rule” and that “the difference in accuracy [between 

Britannica

and 

Wikipedia

]

was not particularly great.”

Arriving amid the revelations of vandalism and errors in 

Wikipedia

, such a finding was, not surpris-

ingly, big news. Within hours of the article’s appearance on 

Nature

’s Web site, media organizations

worldwide proclaimed that 

Wikipedia

was almost as accurate as the oldest continuously published

reference work in the English language.

3

1

1

Jim Giles, “Internet encyclopaedias go head to head,” 

Nature,

December 15, 2005: 900-01.

2

John Seigenthaler, “A false Wikipedia ‘biography,’” 

USA Today,

November 29, 2005

(http://www.usatoday.com/news/opinion/editorials/2005-11-29-wikipedia-edit_x.htm). “Free Encyclopedia
Wikipedia.de Has Copyright Issues,” DW-World/Deutsche Welle, November 29, 2005 (http://www.dw-
world.de/dw/article/0,2144,1796407,00.html). “Wikipedia Caught in Podfather Turf War,” 

Podcasting News,

December

5, 2005 (http://www.podcastingnews.com/archives/2005/12/wikipedia_caugh_1.html). All accessed March 7, 2006.

3

Dan Goodin, “Wikipedia Science Topics As Accurate As Britannica-Report,” Associated Press, December 14, 2005.

Gregory M. Lamb, “Online Wikipedia is not Britannica - but it's close,” 

Christian Science Monitor,

January 5, 2006

(http://www.csmonitor.com/2006/0105/p13s02-stct.html). “Wikipedia Gets Things Right,” 

Red Herring,

December 14,

2005 (http://www.redherring.com/Article.aspx?a=14873&hed=Wikipedia+Is+Fairly+Accurate#). “Assessing Wikipedia’s
Accuracy,” 

All Things Considered,

December 15, 2005 (http://www.npr.org/templates/story/story.php?storyId=5055388).

Julian Dibbell, “Factually Speaking,” 

Village Voice,

December 22, 2005

(http://villagevoice.com/screens/0552,dibbell,71299,28.html). “Fact or fiction? Online encyclopedias put to the test,”

The Age,

December 15, 2005 (http://www.theage.com.au/news/national/online-encyclopedias-put-to-the-

test/2005/12/14/1134500913345.html). All accessed March 7, 2006.

Almost everything about the journal’s investigation, from the criteria for

identifying inaccuracies to the discrepancy between the article text and its headline,

was wrong and misleading.

That conclusion was false, however, because 

Nature

’s research was invalid. As we demonstrate below,

almost everything about the journal’s investigation, from the criteria for identifying inaccuracies to
the discrepancy between the article text and its headline, was wrong and misleading. Dozens of
inaccuracies attributed to the 

Britannica

were not inaccuracies at all, and a number of the articles

Nature

examined were not even in the 

Encyclopædia Britannica

. The study was so poorly carried out

and its findings so error-laden that it was completely without merit. We have produced this docu-
ment to set the record straight, to reassure 

Britannica

’s readers about the quality of our content, and

to urge that 

Nature

issue a full and public retraction of the article.

In rebutting 

Nature

’s work, we in no way mean to imply that 

Britannica

is error-free; we have never

made such a claim. We have a reputation not for unattainable perfection but for strong scholarship,
sound judgment, and disciplined editorial review. These practices are the foundation of any reliable
reference work, and 

Nature

’s careless analysis demeaned them.

Britannica

undergoes continuous revision and fact checking. Our editors work unceasingly to revise

and improve the encyclopedia and to publish the results in a timely way. We work with thousands
of contributors and advisers around the world—scholars and experts all—and maintain a brisk cor-
respondence with our readers as well.

4

We investigate any claims of error that come to our atten-

tion, and when one is valid, we fix the error. Where 

Nature

’s reviewers found genuine inaccuracies

or important omissions in the 

Britannica

, we have corrected them, but as a work of research from

which conclusions may be drawn, 

Nature

’s study was without value. The purpose of this document

is to enumerate the scores of serious errors and misjudgments that undermine 

Nature

’s study so that

its lack of validity can be understood.

Misleading Headline

In the pages below we describe the errors 

Nature

made in its study, but first a word about the mis-

leading way in which it was presented.

Anyone who read the article with even a modicum of care would have noticed a discrepancy
between the headline and the data themselves. While the heading proclaimed that “

Wikipedia

comes

close to 

Britannica

in terms of the accuracy of its science entries,” the numbers buried deep in the

body of the article said precisely the opposite: 

Wikipedia

in fact had 

a third more inaccuracies

than

Britannica

. (As we demonstrate below, 

Nature

’s research grossly exaggerated 

Britannica

’s inaccura-

cies, so we cite this figure only to point out the slanted way in which the numbers were presented.)
Even if 

Wikipedia

were “only” a third more inaccurate than 

Britannica

, this would be a large differ-

2

4

See Michael J. McCarthy, “It’s Not True About Caligula’s Horse; Britannica Checked --- Dogged Researchers Answer

Some Remarkable Queries,” 

Wall Street Journal,

April 22, 1999: A1.

Britannica

was far more accurate than 

Wikipedia

according to the figures;

the journal simply misrepresented its own results.

ence, especially in a study that focused exclusively on factual accuracy, disregarding other important
properties of encyclopedias, such as the organization of information, the quality of writing, and the
readability of the articles. Why 

Nature

tried to minimize this considerable difference in accuracy is

unclear, but the fact is that 

Britannica

was far more accurate than 

Wikipedia

according to the fig-

ures; the journal simply misrepresented its own results.

As we would soon learn, however, this was only the beginning of the investigation’s errors and mis-
representations. In the days after the article was published, 

Britannica

’s science editors, with the help

of our outside advisers and contributors, began reviewing the list of inaccuracies the journal claimed
to have found, with the aim of addressing every claim that had validity. We discovered in 

Nature

’s

work a pattern of sloppiness, indifference to basic scholarly standards, and flagrant errors so numer-
ous they completely invalidated the results. We contacted 

Nature

, asking for the original data, call-

ing their attention to several of their errors, and offering to meet with them to review our findings
in full, but they declined.

The Study and the Data

According to 

Nature

’s description of its study, 42 pairs of articles on scientific subjects, from the

Britannica

and 

Wikipedia

respectively, were reviewed by outside experts, mainly academic scientists,

who were offered anonymity. (Most of them chose to remain anonymous.) According to a docu-
ment posted on 

Nature

’s Web site, reviewers “were asked to look for three types of inaccuracy: factu-

al errors, critical omissions and misleading statements. . . . The reviews were then examined by

Nature

’s news team and the total number of errors estimated for each article.”

5

The reviewers produced reports for the articles assigned to them, and those reviews were excerpted
in the document on the Web. However, contrary to the usual practice of making all data freely
available in order to facilitate a study’s replication by others, 

Nature

declined our repeated requests

to make the full reports available. For more on this, see Appendix A.

Even without the original data, however, 

Britannica

editors analyzed 

Nature

’s findings, using the

truncated versions of the reviewer reports posted on the Web and copies of the articles reviewed that
we obtained from 

Nature

. We identified a multitude of serious flaws in their procedures and conclu-

sions and found that in dozens of cases 

Britannica

information that 

Nature

claimed to be inaccurate

was not inaccurate at all. We review some of 

Nature

’s most significant errors below. A more com-

plete list can be found in Appendix B.

3

5

“Supplementary information to accompany Nature news article ‘Internet encyclopaedias go head to head’”

(http://npg.nature.com/news/2005/051212/exref/supplementary_information.doc). Accessed February 23, 2006.

Contrary to the usual practice of making all data freely available in order

to facilitate a study’s replication by others, 

Nature

declined our repeated requests

to make the full reports available.

Nature

reviewed text that was not even from the 

Encyclopædia Britannica

. 

Several of the arti-

cles 

Nature

sent its reviewers were not from our core encyclopedia, and in one case it was not from

any 

Britannica

publication at all.

Articles on Dolly the Sheep and Steven Wolfram reviewed by 

Nature

were taken not from the

Encyclopædia Britannica

but from previous editions of the 

Britannica Book of the Year

, which

are archived on our site and clearly dated and identified. Yearbook authors are often given
greater latitude to express personal views than writers of encyclopedia articles. In the Wolfram
article, the 

Nature

reviewer disagreed with 

Britannica

’s author on the phrasing of two sentences

in which point of view figured significantly, and on the basis of those disagreements 

Nature

’s

editors counted the two points as “inaccuracies” in 

Britannica

. In addition to the fact that

reviewing yearbook articles in a study of encyclopedias is inappropriate, these particular judg-
ments were simply unfounded. The reviewer was entitled to his or her opinion about how a
point might best be presented, but that opinion did not make our author’s presentation “inac-
curate.”

Nature

’s comments on the article “ethanol” were based on text not from the 

Encyclopædia

Britannica

but from 

Britannica Student Encyclopedia

, a more basic work for younger readers.

One of the reviewer’s comments referred to text that does not appear in any 

Britannica

publi-

cation.

Nature

accused 

Britannica

of “omissions” on the basis of reviews of article excerpts, not the

articles themselves.

In a number of cases only parts of the applicable 

Britannica

articles were

reviewed.

One 

Nature

reviewer was sent only the 350-word introduction to 

Encyclopædia Britannica

’s

6,000-word article on lipids. For 

Nature

to have represented 

Britannica

’s extensive coverage of

the subject with this short squib was absurd, and it invalidated the findings of omissions
alleged by the reviewer, since those matters were covered in sections of the article he or she
never saw.

Other reviewers were sent only sections taken from longer articles. For example, what the

Nature

editors referred to as 

Britannica

’s “articles” on “kin selection” and “punctuated equilibri-

um” are actually separate sections of our article on the theory of evolution, written by one of
the foremost experts on evolution in the world. What they claimed to be an “article” on field-
effect transistors was actually only one section of our article on integrated circuits. For 

Nature

to have excerpted our articles in this way was irresponsible.

4

One of the reviewer’s comments referred to text

that does not appear in any 

Britannica

publication.

Nature

rearranged and re-edited 

Britannica

articles.

In some cases reviewers were sent patch-

works of text taken from two or more articles and pieced together in a way that made a mockery of
the original entries. The “article” on “aldol reaction” that the journal sent its reviewer consisted of
passages taken selectively from two different 

Encyclopædia Britannica

articles and joined together

with text evidently written by 

Nature

’s editors. This was dishonest, and it completely misrepresented

Britannica

’s published coverage of the subject.

Nature

failed to check the factual assertions of its reviewers.

Everyone makes mistakes, even

experts, which is why all factual assertions should be verified. 

Nature

, however, decided not to do

this; they did not even require reviewers to provide sources for their assertions because “it would
have been simply too time consuming.”

6

Instead, 

Nature

assumed that what its reviewers said was

true and, when it contradicted something in the 

Britannica

, that the reviewer was right and

Britannica

was wrong. The result was predictable.

7

Examples:

Nature

’s review of the 

Britannica

article “Pythagorean theorem” claimed the 

Britannica

mis-

spelled an Italian town that the reviewer said should be spelled “Crotona.” However, according
to the U.S. Board of Geographic Names, the preferred spelling is in fact “Crotone,” as

Britannica

spelled it. Other reliable sources also give “Crotone” as the right spelling. For

Nature

’s editors to have ruled this an error on one reviewer’s say-so, without confirming the

spelling, was inexcusable.

For the article on Subrahmanyan Chandrasekhar, 

Nature

’s reviewer quibbled with the dates

Britannica

gave for one of Professor Chandrasekhar’s academic appointments and for the pub-

lication of his book 

Principles of Stellar Dynamics

. Once again, on the basis of these unverified

objections, 

Nature

ruled 

Britannica

to be in error, but we have solid sources for both dates, and

we stand by them. See Appendix B for details.

Nature

failed to distinguish minor inaccuracies from major errors.

By counting up the alleged

inaccuracies for both encyclopedias, 

Nature

treated all mistakes equally and failed to observe that

Wikipedia

had many more shortcomings of a fundamental kind. Reviewers told the journal that

many of the 

Wikipedia

articles were “poorly structured and confusing”—a fact that made those arti-

5

6

“Supplementary information,” 2.

7

Nature

’s editors appear to have thought that since their reviewers were scientists, those reviewers’ judgments trumped

the encyclopedia where there was a disagreement. This was presumptuous, since Britannica engages expert advisers and
contributors who are in every way equal to 

Natur

e’s reviewers. Our distinguished contributors have included more than

110 Nobel laureates.

The “article” on “aldol reaction” that the journal sent its reviewer consisted

of passages taken selectively from two different 

Encyclopædia Britannica

articles

and joined together with text evidently written by 

Nature

’s editors.

cles resistant to basic fact checking and thus not suitable for comparison with 

Britannica

—yet the

fact was buried deep in the article and its methodological implications ignored.

Nature

counted “errors” and “critical omissions” that did not exist.

As we have said, where

reviewers found genuine inaccuracies in the 

Britannica

, we corrected them, but dozens of the so-

called inaccuracies they attributed to us were nothing of the kind; they were the result of reviewers
expressing opinions that differed from ours about what should be included in an encyclopedia arti-
cle. In these cases 

Britannica

’s coverage was actually sound, most often reflecting the considered

judgment of editors who have extensive experience in publishing an encyclopedia, in deciding what
information should be included in it for the general reader, and in how it should be presented.

Nature

’s reviewers—who were scientists, not encyclopedists—were certainly entitled to their opin-

ions on these matters, but for 

Nature

to have ascribed inaccuracies to 

Britannica

simply on the basis

of their opinions was invalid. For example:

According to the reviewer of the 

Britannica

article “Nobel Prize,” the fact that the 1935 Peace

Prize was awarded to Carl von Ossietzky in 1936 should have been stated. We disagree. To
raise this minor fact and then be required to explain it would, at that point in the Nobel Prize
article, have distracted the reader from the main discussion. This was not an omission; it was
an editorial judgment. (N.B.: The fact that the award was conferred in 1936 is reported in
Ossietzky’s biographical article, where it belongs.)

The reviewer of the article on Paul Dirac objected that certain areas of Dirac’s work were not
covered. Our coverage, however, was appropriate for a general-reference encyclopedia. By
design, the 825-word article explained, for the lay reader, Dirac’s most significant contribu-
tions, not all of them.

The reviewer of the article on the Haber-Bosch process suggested that the article should have
shown the chemical equation for the reaction, and 

Nature

therefore called its absence from the

article an omission. Not so. The article’s verbal description of the process was clear and suffi-
cient for the general reader.

6

Conclusion

“No test is perfect and we acknowledge that any of our reviewers could themselves have made occa-
sional errors,” said the editors of 

Nature

about their study. “But by choosing reviewers who were

highly qualified in the specific area described by each entry, we aimed to subject the encyclopaedia
entries to the fairest and most stringent test that we could.”

8

Indeed, perfection is unattainable, and a few mistakes in 

Nature

’s analysis could perhaps have been

overlooked. But alas, as we have shown above, the study’s shortcomings went well beyond “occa-
sional errors.” The entire undertaking—from the study’s methodology to the misleading way 

Nature

“spun” the story—was misconceived. Among other things, while it is important to engage “reviewers
who were highly qualified,” that alone is not enough: as every editor at 

Britannica

knows, even the

assertions of experts must be confirmed and their observations considered in the proper context for
a general-reference work like 

Britannica

. 

Nature

failed to take these and so many of the other steps

that would have been required to make its research valid. The results were the errors we describe
above and in Appendix B.

We now call on 

Nature

to fulfill its commitment to good scholarship and send us the unabridged

reviewer reports on which the study was based. And as we have shown here, the facts call for a com-
plete retraction of the study and the article in which it was reported. We call on 

Nature

to make the

retraction and make it promptly.

7

8

“Supplementary information,” 1.

Appendix A: The Original Data

We began our analysis of 

Nature

’s work with an attempt to get the basic data on which the study

was based, none of which accompanied the article itself. More than a week after the article was pub-
lished, 

Nature

posted on its Web site a document that claimed to provide “more detailed informa-

tion about how our survey was carried out.”

9

However, the document did not contain the complete

reports submitted by 

Nature

’s reviewers. The editors explained how they created the modified report

for public consumption in part as follows:

“ . . . we sometimes disregarded items that our reviewers had identified as errors or critical
omissions. In particular, as we were interested in testing the entries from the point of view of
‘typical encyclopaedia users’, we felt that experts in the field might sometimes cite omissions as
critical when in fact they probably weren’t - at least for a general understanding of the topic.
Likewise, the ‘errors’ identified sometimes strayed into merely being badly phrased - so we
ignored these unless they significantly hindered understanding.”

10

This clearly indicates that 

Nature

’s editors exercised subjective judgment in redacting the original

reports to produce the versions posted on the Web. The original reports, therefore, constituted key
data for any complete replication or reanalysis of the findings, so we asked for a copy of those
reports. 

Nature

refused to give them to us.

8

9

”Supplementary information,” 1. Accessed February 23, 2006.

10

Ibid., 2

Appendix B: 

Nature

’s Errors

The 

Nature

study was based on expert reviews of articles from the 

Encyclopædia Britannica

and

Wikipedia

. The reviews themselves are secret, but 

Nature

has excerpted them on its Web site. That

document is revealing in what it suggests about the questionable methodology of the study.
Apparently, 

Nature

’s editors took almost every assertion by its reviewers at face value and classified

as an inaccuracy any criticism of a 

Britannica

article by one of its reviewers, even when the review-

er’s statement should clearly have been regarded as an expression of opinion. The editors did not
require corroborating sources from their reviewers, and they apparently did little fact checking of
their own. As a result, they attributed to 

Britannica

dozens of inaccuracies that were in fact nothing

of the kind. In this section of our report we reproduce from the document 

Nature

posted on its

Web site dozens of comments from reviewers that were the basis of alleged inaccuracies in

Britannica

, along with our response. Article titles in this appendix are those that 

Nature

gave the

texts they sent their reviewers. The titles that appear in brackets are the actual titles of the

Britannica

articles.

Article: Acheulean Industry

Reviewer comment:

I would not use the term ‘early 

Homo sapiens

’. Instead, use 

Homo

heidelbergensis

.

Britannica response:

We do not accept this criticism, which only reflects the point of view of the

reviewer. The term “early 

Homo sapiens

” cannot simply be swapped for “

Homo heidelbergensis

”

without explanation. As is stated elsewhere in the 

Britannica

, many paleoanthropologists do cate-

gorize some early 

H. sapiens

as 

H. heidelbergensis

, though many do not. Likewise, some insist that

many hominins called 

H. erectus

are really 

H. ergaster

, though some do not. In a short article like

this we have decided not to distract the lay reader by raising such complex issues. We leave these
issues to our more substantial articles on human evolution and the various 

Homo

species, which

have been written and revised by Russell Tuttle of the University of Chicago, Ian Tattersall of the
American Museum of Natural History, Erik Trinkaus of Washington University, and G. Philip
Rightmire of the State University of New York-Binghamton.

Article: Aldol [actually “chemical compound: Aldol reaction” and “acid-base reaction: Aldol
condensation, base-catalyzed”]

Reviewer comments:

1. The aldol REACTION is not the same as the aldol CONDENSATION.

2. Sodium hydroxide is by no means the only base to be used in the aldol and acid catalysed aldol

reactions also occur (usually with concomitant loss of water).

3. The reaction steps in the second reaction sequence should be equilibria up to the dehydration

step.

9

4. In particular, there is no mention of the acid catalysed process and scant mention of related reac-

tions.

Britannica response:

We do not accept the validity of this review. The reviewer was given a cut-

and-paste piece that began with part of a sentence from one 

Encyclopædia Britannica

article, fin-

ished that sentence with an extract from another article, then reverted to an extract from the first
article after a transitional clause inserted by the 

Nature

editors. It is simply unacceptable for

Nature

to cut and paste different 

Britannica

entries, add its own editorial material, and then pass

the resulting pastiche off under 

Britannica

’s name.

Article: Archimedes Principle [“Archimedes’ principle”]

Reviewer comments:

1. In the fourth sentence the word ‘floating’ is used to mean ‘at rest’, and does not necessarily mean

that in common parlance.

2. The very last sentence is true only for an object at rest; when a body is moving there are pressure

forces, as well as viscous stresses, associated with the motion.

Britannica response:

We do not accept these criticisms. Our article begins by defining Archimedes’

principle in relation to an object immersed in a fluid at rest, a perfectly reasonable method for
explaining this fundamental principle to nonspecialists. Our recent revision of this article, which
was in process at the time of the review, retains this method of explanation.

Article: Cambrian Explosion [actually “community ecology: The Cambrian explosion”]

Reviewer comment:

Evolution of hard parts at beginning of Cambrian involved much more than

development of calcium carbonate.

Britannica response:

The article does not claim or imply that calcium carbonate explains all there

is to know about hard parts. CaCO

3

is clearly used only as an example.

Reviewer comment:

Role of oxygen in Cambrian explosion may well have been important, but it

involved much more than the evolution of hard parts.

Britannica response:

The article does not claim that oxygen had a role only in the development of

hard parts.

Reviewer comment:

Many suspension feeders, e.g. bryozoans, brachiopods, radiated in Ordovician,

not Silurian.

Britannica response:

Some forms of suspension feeders radiated in the Ordovician, others in the

Silurian. We stand by the author’s decision to focus on the Silurian in the context of his article
section.

10

Article: Chandrasehkar, Subrahmanyan [“Chandrasekhar, Subrahmanyan”]

Reviewer comment:

Chandrasekhar joined the staff of the University of Chicago, rising from assis-

tant professor of astrophysics (

1937

) to Morton D. Hull etc.

Britannica response:

This claim of error is wrong. Chandrasekhar’s Nobel biography and Eugene

Parker, S. Chandrasekhar Distinguished Service Professor Emeritus, University of Chicago, note
that Chandrasekhar was a research associate, not an assistant professor, in 1937. He became assis-
tant professor in 1938.

Reviewer comment:

Books: Principles of Stellar Dynamics (

1943

).

Britannica response:

We do not accept this. The Library of Congress, our source for publication

dates, cites 1942 as the year of publication for this book.

Article: Creutzfeldt-Jakob Disease (CJD)

Reviewer comment:

The statement about mutations leading to increased susceptibility to infection

is speculative. There is no evidence that mutations lead to sporadic CJD.

Britannica response:

We do not accept this criticism of our phrasing. Our adviser agrees that our

conditional phrasing is sufficient.

Article: Cloud

Reviewer comments:

1.

‘As a mass of air ascends, the lower pressures prevailing at higher levels allow it to expand. In expand-
ing, the air cools adiabatically (i.e., without heat exchange with the surrounding air) until its tempera-
ture falls below

[to]

the dew point

2.

upon which the air becomes supersaturated

[saturated]

.

Britannica response:

We do not accept these criticisms (which are really just one criticism, not

two). We have published a revision of this article that retains the emphasis on supersaturation
rather than the transitional stage of saturation.

Reviewer comment:

The presence of cloudiness marks smaller diurnal temperature variations. A low

overcast layer of cloud acts like a blanket, preventing the temperature from dropping much at
night. A clear [night] evening sky, on the other hand, often leads to rapid cooling, with dew,
frost, or even fog forming the following morning as a result.

11

Britannica response:

We do not accept this criticism, which misquotes our article. Our article actu-

ally says that a clear evening sky “indicates” (not “leads to,” as the reviewer claims) rapid cooling.
Our recent revision has retained the emphasis on evening, and we stand by this revision.

Article: Dirac, Paul [“Dirac, P.A.M.”]

Reviewer comment:

There is nothing here about Dirac’s work on the monopole - an important

omission.

Britannica response:

This is not a critical omission. This 825-word article sets out to explain the

most significant contributions of Dirac’s career, and it does just that.

Reviewer comment:

I was surprised to see nothing at all about Dirac’s large number hypothesis

(1937).

Britannica response:

We do not accept this criticism, for the reason cited above.

Reviewer comment:

Dirac co-invented QM independently of the Göttingen group after he read

Heisenberg’s paper. It is therefore misleading to say that he was behind them, except in that first
paper.

Britannica response:

We stand by this passage, which explains a complicated situation in a way

that is appropriate for the lay reader; to do more would introduce an order of detail that does not
belong in this article.

Reviewer comment:

Dirac produced his transformation /before/ he wrote his book.

Britannica response:

We stand by this passage as it is. To state as we do that Dirac developed the

transformation theory of quantum mechanics in his book is not at all to imply that he had not
worked out the theory before putting pen to paper.

Reviewer comment:

It does not mention his discovery of the least action formulation of QM - an

extremely important contribution

Britannica response:

We do not accept this criticism, for the reason cited above. Note: As part of

our physics revision program independent of this review, Alexei Kojevnikov of Georgia State
University has written a new article on Dirac that will be published shortly.

Article: Dolly the Sheep [actually not an 

Encyclopædia Britannica

article but a 1998 entry

from 

Britannica Book of the Year

entitled “Life Sciences: A Sheep Named Dolly”]

Reviewer comment:

Mitochondria would have been contributed by the donor mammary gland cell,

though these do not appear to have survived (much in the way that sperm mitochondria do not
contribute to those in the adult animal).

12

Britannica response:

We do not accept this criticism of our 1998 yearbook article. The donor

mammary gland cell may well have “contributed” mitochondria, but the mitochondria actually
present in Dolly’s cells were derived from the donor egg. Our yearbook article from eight years
ago cannot be faulted for not referring to mitochondria that did not survive; the article rightly
refers to mitochondria that did survive and were present in Dolly’s cells. Furthermore, because
this is a dated yearbook article, it had no place in a study of encyclopedias.

Article: Ethanol

Reviewer comments:

1. The word ‘alcohol’ is derived from the Arabic ‘al kuhl’ but I think the linking of this ‘kuhl’ with

the traditional eye-makeup ‘kohl’ is dubious.

2. The author is misunderstanding the term ‘methylated spirits’ and seems to think that this is alco-

hol to which methanol has been deliberately added to render it undrinkable. This does not hap-
pen. It is called ‘methylated’ because it still contains 

traces

of methanol that have not been

removed.

Britannica response:

We do not accept the validity of these criticisms. The reviewer has comment-

ed on text from the 

Britannica Student Encyclopedia

, which is a much more general product for a

younger audience, not on text from the 

Encyclopædia Britannica

, and apparently (for comment

#2) on text from some other source unknown to us.

Article: Field Effect Transistor [actually “integrated circuit: Field-effect transistors”]

Reviewer comment:

The second paragraph is wrong in that it does not describe the operation of a

known transistor. Some aspects appear correct but the underlying principle described is wrong.

Britannica response:

The author of this article, Christopher Saint of the IBM West Coast Design

Center, is willing to accept valid notices of inaccuracy in his article, but he simply disagrees with
this criticism. We stand by this paragraph and our author.

Article: Haber Process [“Haber-Bosch process”]

Reviewer comment:

It really should include an equation that shows N

2

+ 3 H

2

-> 2NH

3

.

Britannica response:

We stand by this article, which clearly describes the Haber-Bosch process and

its importance. The article’s verbal description of this process for making ammonia is so clear that
the reviewer’s recommended addition of a chemical equation is unnecessary.

13

Article: Kin Selection [actually “evolution: Kin selection and reciprocal altruism”]

Reviewer comment:

It’s stretching things a bit to say in the last para that ‘A queen typically mates

with a single male during her lifetime…’ This is true of some ants, but is not a general rule for
social insects.

Britannica response:

We do not accept this criticism. The author of this article, Francisco Ayala,

was explaining a general case that often obtains, rather than a complicated case that would be
more appropriate for an advanced thesis.

Reviewer comment:

Yes, [

Nature reviewer unclear here

] in using the language of individual-level fit-

ness and selection; but this was also a shortcoming of Hamilton’s original formulation. Thus to
say ‘They all carry the same genes…’ (para 1) is misleading because what matters is not the total-
ity of genes shared but the probability that relatives share a specific gene (strictly allele), in this
case the one coding for the altruistic trait. By the same token, ‘individual fitness’ is a proxy for
allele fitness, again, in this case, specifically the allele for the altruistic trait. Kin selection is THE
paradigm of the gene selection argument; it actually makes no sense when couched at the level of
individual fitness. The problem cascades through the piece, thus: Par2, lines 4-5 - should be ‘A
parent has a probability of 0.5 (or a half ) of sharing any given gene (again actually allele) with
each progeny …’ and last line - should be ‘…because it increases the probability of transmission
of the parental gene for caring.’

Britannica response:

There is no inaccuracy here. We stand by our author, Francisco Ayala, who

insists that the reviewer is wrong through and through: the altruistic behavior is favored by natu-
ral selection because relatives share (in fractions depending on the degree of relatedness) all their
genes.

Reviewer comment:

Para 4, first sentence - I’d say instead that ‘Altruism also occurs among unrelat-

ed individuals when the benefit of reciprocal cooperation is greater than the average benefit from
refusing to cooperate.’ [

not ‘ when the altruist’s costs are smaller’

] which are the conditions for the

Prisoners’ dilemma model to predict mutual cooperation as a stable alternative to defection.

Britannica response:

This quibbling over choice of language does not expose inaccuracy. We stand

by this passage as written by Francisco Ayala, who prefers to retain his original wording.

Article: Lipid

Reviewer comments:

1. No mention of “saturated” and “unsaturated” fats, or more precisely fatty acids, is made.

2. There is no mention of the propensity of lipids to “self assemble” which is the basis of their abili-

ty to form membranes

14

3. The article uses outdated nomenclature only and fails to use the new more logical system such as

phosphatidylcholine in place of lecithin.

Britannica response:

We do not accept this review. Our article on lipids is 6,000 words long; the

Nature

reviewer was sent only the 350-word introduction.

Article: Lomborg, Bjorn [actually not an article from the 

Encyclopædia Britannica

but an

entry from the 2004 

Britannica Book of the Year

entitled “Biographies: Lomborg, Bjørn”]

Reviewer comment:

It might have done better to qualify Bjorn’s Greenpeace past as not true to call

him “a committed Greenpeace environmentalist”. I think the “committed” is overstating it.

Britannica response:

We do not accept this. This is the reviewer’s opinion, and he or she is entitled

to it, but it does not make our author’s characterization of Lomborg inaccurate.

Article: Meliaceae

Reviewer comment:

So short as to be of very little help in identifying the family: it could apply to

any of about ten other families, or more.

Britannica response:

We do not accept this criticism of our short article on this specific plant fami-

ly. We are not a botanical encyclopedia and do not pretend to be. Other articles in our set pro-
vide information on specific plant species mentioned in this entry, and we also have a long article
on the order (Sapindales) to which this family belongs.

Article: Mendeleev, Dmitry [“Mendeleyev, Dmitry Ivanovich”]

Reviewer comment:

Declaring him the 17th child is either incorrect or misleading. He is the 13th

surviving child of 17 total.

Britannica response:

We disagree with the reviewer’s implication that there is full agreement that

Mendeleyev was the 13th surviving child. Our new article makes it clear that scholars are not
uniform in their views on whether Mendeleyev was the 13th or 14th surviving child.

Reviewer comment:

The presentation of Mendeleev as a political radical is highly misleading.

Britannica response:

The article does not claim that Mendeleyev was a “political radical”-only that

he was a Russian of progressive views who supported his students’ right to present a petition.
Note: As part of our chemistry revision program independent of this review, we have published a
new article on Mendeleyev by Bernadette Bensaude-Vincent of University of Paris X - Nanterre.

15

Article: Neural Network

Reviewer’s comment:

The following sentence is misleading: “If the total of all the weighted inputs

received by a particular neuron surpasses a certain threshold value, the neuron will send a signal
to each neuron to which it is connected in the next layer.” This suggests that the described proce-
dure is the only one used, which is not the case.

Britannica response:

We do not accept this. The article does not imply that the described proce-

dure is the only one used.

Reviewer comment:

The following sentence is also misleading: “First, a network can be equipped

with a feedback mechanism, known as a back-propagation algorithm that enables it to adjust the
connection weights back through the network, training it in response to representative examples.”
Once again, there are many other training algorithms available in addition to backpropagation.

Britannica response:

We do not accept this criticism. The article does not imply that this particular

algorithm is the only one used.

Article: Nobel Prize

Reviewer comment:

Bibliography lacks the two most important works on the subject, Crawford’s

The Beginning of the Nobel Institution (1984) and Friedman’s The Politics of Excellence (2001),
as well as the classic paper in 

Nature

(1981).

Britannica response:

We do not consider these critical omissions. Our bibliography is quite suffi-

cient, already containing two dozen titles, including two books by Elisabeth Crawford.

Reviewer comment:

Omission: That the Nobel Committee for Peace is appointed by the

Norwegian Storting (Parliament). Although the committee is allegedly non-political, the appoint-
ments are very political.

Britannica response:

This is not a critical omission. Our article does not discuss the means by

which members of any of the awarding institutions receive their positions. To do so only for the
Norwegian Nobel Committee would introduce a lack of balance and unnecessary detail into the
article.

Reviewer comment:

Unclear/misleading: The 1935 Peace Prize to Ossietzky was awarded in 1936

(it had been reserved in ‘35). This makes more sense when referring to Hitler’s ban on German
participation in ‘37.

Britannica response:

We do not consider this a misleading statement. The important fact is that

Ossietzky was awarded the 1935 Peace Prize. To state that the 1935 prize had to be awarded in
1936 would oblige us to explain the reason, which at this point would only distract the reader
from the main point of the discussion.

16

Reviewer comment:

“Several thousand people are engaged in the committees’ efforts to determine

the originality and significance of each nominee’s contribution, and outside experts are frequently
consulted….” Misleading - thousands participate in the nomination process, and by no means
are all those who send in nominations impartial, but the actual determination of originality and
significance remains with the committee. Use of outside experts is relatively recent and probably
not ‘frequent’, at least in the sciences. The entry gives the impression that the process of evalua-
tion entails a huge communal effort; this is not correct. More correct would be several thousand
participate in the process of proposing candidates whose works are claimed to be of highest origi-
nality and significance. But evaluation of these candidates remains largely confined to the
Swedish or Norwegian committees.

Britannica response:

We have corrected the statement that several thousand people are “engaged”

in the committees’ efforts. However, we stand by our statement that outside experts are frequent-
ly consulted during the process-a reasonable statement supported by information available on the
Web sites of the Nobel Foundation and the Norwegian Nobel Institute.

Article: Pheromone

Reviewer comment:

One might get the impression that a pheromone is a substance, while it usually

consists of several in a blend.

Britannica response:

We do not accept this criticism. This article does not even discuss the compo-

sition of pheromones.

Article: Prion

Reviewer comment:

The conclusion that Alzheimer disease or Parkinson disease may arise from

molecular mechanisms similar to those that cause prion diseases is not valid. All these disease[s]
may share common pathways leading to neurodegeneration but AD or PD are not transmissible
diseases (a hallmark of prion diseases).

Britannica response:

We stand by this article’s statement, which does not even address causal fac-

tors-only molecular mechanisms.

Reviewer comment:

It should be more clearly stated that prion proteins exist in a normal isoform

which is present in all cell types of the body and may adopt a pathogenic conformation that is
deleterious to neuronal cells and thus associated with the disease. (Both proteins are called prion
proteins, the use of the term “prion protein” to refer only to the pathogenic form is misleading).

Britannica response:

We stand by this article’s clearly written account of how prions destroy nerve

tissue.

17

Reviewer comment:

The entry should refer to Griffith and Alper as the 1st scientists to propose

that the infectious agent responsible for TSE may be solely composed of proteins. Prusiner then
purified the prion protein form [sic] the infectious agent.

B

ritannica response:

We stand by our editorial decision to leave references to Griffith and Alper

out of this article, which focuses on the protein and the principal person associated with it. The
contribution of Griffith and Alper to Prusiner’s research is described in detail elsewhere in the

Britannica

corpus.

Article: Punctuated Equilibrium [actually “evolution: Gradual and punctuational evolution”]

Reviewer comment:

I think this misleads the reader by using terms like “The punctualists main-

tain...” giving a negative impression of proponents of PE. It seems that the entry is organised as
an argument against PE - and doesn’t bother much to explain what PE is about.

Britannica response:

We stand by this article section. It is fairly and clearly written by our author,

Francisco Ayala, who has concluded that the reviewer’s comment is an opinion and does not con-
sider this passage to be inaccurate or misleading.

Article: Pythagoras’ Theorem [“Pythagorean theorem”]

Reviewer comment:

The Italian town is Crotona, not Crotone.

Britannica response:

This accusation is simply wrong. The proper modern spelling of this town in

Italy is Crotone, according to the U.S. Board on Geographic Names and several reputable atlases.

Article: Quark

Reviewer comment:

Quarks possess other quantum properties, not discussed here, which are as fun-

damental as those which are described. In particular, quarks possess “charges” which give rise to
their weak interactions.

Britannica response:

This is not a critical omission, and it is not addressed in our recent revision of

the article, which rightly focuses on the strong force behavior of quarks as their most important
characteristic.

Reviewer comment:

Second paragraph: The following statements are misleading: “Quarks appear to

be truly fundamental. They have no apparent structure; that is, they cannot be resolved into
something smaller.” The prevailing view is that quarks are unlikely to be truly fundamental.
While no experiment has to date revealed any substructure to quarks, there are strong theoretical
reasons to believe that quarks are not fundamental entities, and enormous experimental effort

18

(including the multi-nation program of the Large Hadron Collider at CERN, in Geneva) is cur-
rently being devoted to the search for smaller or more fundamental constituents of matter.

Britannica response:

We do not accept this criticism, and it is not addressed in our recent revision

of the article. At the present limits of experimentally available energies, quarks are indeed indivisi-
ble. Some theorists may say that quarks can be broken into smaller entities, but this is hardly the
prevailing view, and the machines that would allow these theories even to be tested will not be
available for some time to come.

Article: Royal Greenwich Observatory

Reviewer comment:

It was the oldest observatory, or the oldest astronomical institution NOT the

oldest scientific institution (that was the Royal Society, est.1666).

Britannica response:

We do not accept this. The Royal Greenwich Observatory was indeed the old-

est scientific institution in the U.K. The Royal Society was not formally instituted with a home
and government funds; it was a chartered association of interested persons who met in various
places and raised their own funds.

Article: Royal Society

Reviewer comment:

In para. 3, some of the information about current publications is wrong.

Britannica response:

We do not accept this criticism. Our characterization of the 

Philosophical

Transactions

and the 

Proceedings

is sufficient.

Article: Thyroid [“thyroid gland”]

Reviewer comment:

Does not contain the information that most thyroid hormone is in the form of

thyroxine and this is how it is most easily transported e.g. across the blood/brain barrier.
However T3 is the biologically active form of the hormone and is produced, partly directly, but
also by de-iodination of thyroxine which occurs in tissues.

Britannica response:

The article does indeed “contain the information that most thyroid hormone

is in the form of thyroxine” and that “T3 is the biologically active form.” The metabolism of thy-
roxine to T3 elsewhere in the body is not a topic for this article, which is on the thyroid gland.
Thyroxine-T3 metabolism is discussed elsewhere in the 

Encyclopædia Britannica

—e.g., in our arti-

cle on the endocrine system. Our previously arranged revision does not add anything on this thy-
roxine-T3 conversion, and we stand by this revision.

Reviewer comment:

It does not mention the importance of iodine intake.

19

Britannica response:

Iodine uptake is indeed discussed. Our recent revision retains this discussion,

which we feel is appropriate.

Reviewer comment:

It does not mention the newborn screening for congenital hypothyroidism.

Britannica response:

An article titled “thyroid gland” does not need a reference to newborn screen-

ing for congenital hypothyroidism.

Article: Vesalius, Andreas

Reviewer’s comment:

The name of Galen is mentioned and essential for Vesal´s achievements there-

fore it should be mentioned that he lived from 129/130 to 199/200 A D , long before the age of
Vesal and nearly nobody had dared for centuries to doubt Galen´s results.

Britannica response:

We stand by this article, which refers to Galen as “the Greek physician who

had served the emperor Marcus Aurelius in Rome and whose books on anatomy were still consid-
ered as authoritative in medical education in Vesalius’ time.” We do not consider it necessary or
even helpful to distract the reader at this point with Galen’s birth and death dates.

Reviewer comment:

We do not know, what Vesal´s goal was, therefore “Vesalius had attained his

goal” should be omitted it is a speculation.

Britannica response:

We stand by this. The reference to Vesalius having attained his goal is not

“speculation”; it is a reasonable scholarly conclusion expressed by the author.

Article: Wolfram, Stephen [actually not an article from the 

Encyclopædia Britannica

but an

entry from the 2003 

Britannica Book of the Year

entitled “Biographies: Wolfram, Stephen”]

Reviewer comments:

1. Paragraph 1, line 5 has an error. Wolfram does believe in math-based science, but not in

TRADITIONAL math, so change “math-based science” to “science based on traditional mathe-
matics.”

2. Last paragraph: delete “corporate sellout and” (not true) and change “surely” to “may have.”

Britannica response:

We do not accept this. These are the reviewer’s opinions, and he or she is

entitled to them, but they do not make our author’s characterization of Wolfram inaccurate. For

Nature

to judge these items inaccuracies on the basis of one reviewer’s opinion is invalid.

Furthermore, this is not an encyclopedia article; it is a yearbook article and was identified as such
on our site. It should not have been included in a study of encyclopedias.

20