Source criticism

Source criticism (or information evaluation) is the process of evaluating an information source, i.e. a document, a person, a speech, a fingerprint, a photo, an observation or anything used in order to obtain knowledge. In relation to a given purpose, a given information source may be more or less valid, reliable or relevant. Broadly, "source criticism" is the interdisciplinary study of how information sources are evaluated for given tasks (cf. next sections).

Meaning

Problems in translation: The Danish word “kildekritik” like the Norwegian word “kildekritikk” and the Swedish word “källkritik” derived from the German “Quellenkritik” and is closely associated with the German historian Leopold von Ranke (1795–1886). Hardtwig writes: "His [Ranke's] first work Geschichte der romanischen und germanischen Völker von 1494–1514 (History of the Latin and Teutonic Nations from 1494 to 1514) (1824) was a great success. It already showed some of the basic characteristics of his conception of Europe, and was of historiographical importance particularly because Ranke made an exemplary critical analysis of his sources in a separate volume, Zur Kritik neuerer Geschichtsschreiber (On the Critical Methods of Recent Historians). In this work he raised the method of textual criticism used in the late eighteenth century, particularly in classical philology to the standard method of scientific historical writing" (Hardtwig, 2001, p. 12739).

The larger part of the nineteenth and twentieth centuries would be dominated by the research-oriented conception of historical method of the so-called Historical School in Germany, led by historians as Leopold Ranke and Berthold Niebuhr. Their conception of history, long been regarded as the beginning of modern, `scientific' history, harked back to the `narrow' conception of historical method, limiting the methodical character of history to source criticism" (Lorenz, 2001).

Bible studies dominate the use of "source criticism" in America (cf. Hjørland, 2008). The term is thus relatively seldom used in English about historical methods and historiography (cf. Hjørland, 2008). This difference between European and American use of "source criticism" is somewhat strange considering the influence of Ranke on both sides of the Atlantic Ocean. It has been suggested that differences in the use of the term are not accidental but due to different views of the historical method. In the German/Scandinavian tradition this subject is seen as important, whereas the Anglo-American tradition it is believed that historical methods must be specific and associated with the subject studied, for which reason there is no general field of "source criticism".

In the Scandinavian countries and elsewhere source evaluation (or information evaluation) is also studied interdisciplinarily from many different points of view, partly caused by the influence of the Internet. It is a growing field in, among other fields, library and information science. In this context source criticism is studied from a broader perspective than just, for example, history or biblical studies.^[1][2]

Principles

The following principles are cited from two Scandinavian textbooks on source criticism, Olden-Jørgensen (1998) and Thurén (1997) written by historians:

• Human sources may be relics (e.g. a fingerprint) or narratives (e.g. a statement or a letter). Relics are more credible sources than narratives.
• A given source may be forged or corrupted; strong indications of the originality of the source increases its reliability.
• The closer a source is to the event which it purports to describe, the more one can trust it to give an accurate description of what really happened
• A primary source is more reliable than a secondary source, which in turn is more reliable than a tertiary source and so on.
• If a number of independent sources contain the same message, the credibility of the message is strongly increased.
• The tendency of a source is its motivation for providing some kind of bias. Tendencies should be minimized or supplemented with opposite motivations.
• If it can be demonstrated that the witness (or source) has no direct interest in creating bias, the credibility of the message is increased.

We may add the following principles:

• Knowledge of source criticism cannot substitute subject knowledge:

"Because each source teaches you more and more about your subject, you will be able to judge with ever-increasing precision the usefulness and value of any prospective source. In other words, the more you know about the subject, the more precisely you can identify what you must still find out". (Bazerman, 1995, p. 304).

• The reliability of a given source is relative to the questions put to it.

"The empirical case study showed that most people find it difficult to assess questions of cognitive authority and media credibility in a general sense, for example, by comparing the overall credibility of newspapers and the Internet. Thus these assessments tend to be situationally sensitive. Newspapers, television and the Internet were frequently used as sources of orienting information, but their credibility varied depending on the actual topic at hand" (Savolainen, 2007).

The following questions are often good ones to ask about any source according to the American Library Association (1994) and Engeldinger (1988):

1. How was the source located?
2. What type of source is it?
3. Who is the author and what are the qualifications of the author in regard to the topic that is discussed?
4. When was the information published?
5. In which country was it published?
6. What is the reputation of the publisher?
7. Does the source show a particular cultural or political bias?

For literary sources we might add complementing criteria:

1. Does the source contain a bibliography?
2. Has the material been reviewed by a group of peers, or has it been edited?
3. How does the article/book compare with similar articles/books?

Levels of generality

How general are principles of source criticism? Some principles are universal, other principles are specific for certain kinds of information sources. One may ask whether principles of source criticism are unique to the humanities?

There is today no consensus about the similarities and differences between natural science and humanities. Logical positivism claimed that all fields of knowledge were based on the same principles. Much of the criticism of logical positivism claimed that positivism is the basis of the sciences, whereas hermeneutics is the basis of the humanities. This was, for example, the position of Jürgen Habermas. A newer position, in accordance with, among others, Hans-Georg Gadamer and Thomas Kuhn understands both science and humanities as determined by researchers' preunderstanding and paradigms. Hermeneutics is thus a universal theory. The difference is, however, that the sources of the humanities are themselves products of human interests and preunderstanding, whereas the sources of the natural sciences are not. Humanities are thus "doubly hermeneutic".

Natural scientists, however, are also using human products (such as scientific papers) which are products of preunderstanding (and, for example, academic fraud).

Contributing fields

Epistemology

Epistemological theories are the basic theories about how knowledge is obtained and thus the most general theories about how to evaluate information sources. Empiricism evaluates sources by considering the observations (or sensations) on which they are based. Sources without basis in experience are not seen as valid. Rationalism provides low priority to sources based on observations. In order to be meaningful observations must be grasped by clear ideas or concepts. It is the logical structure and the well definedness that is in focus in evaluating information sources from the rationalist point of view. Historicism evaluates information sources on the basis of their reflection of their sociocultural context and their theoretical development. Pragmatism evaluate sources on the basis of how their values and usefulness to accomplish certain outcomes. Pragmatism is skeptical about claimed neutral information sources.

The evaluation of knowledge or information sources cannot be more certain than is the construction of knowledge. If we accept the principle of fallibilism we also have to accept that source criticism can never 100% verify knowledge claims. As discussed in the next section is source criticism intimately linked to scientific methods.

The presence of fallacies of argument in sources is another kind of philosophical criteria for evaluating sources. Fallacies are presented by Walton (1998). Among the fallacies are the ‘ad hominem fallacy’ (the use of personal attack to try to undermine or refute a person’s argument) and the ‘straw man fallacy’ (when one arguer misrepresents another’s position to make it appear less plausible than it really is, in order more easily to criticize or refute it.) See also fallacy.

Research methodology

Research methods are methods used to produce scholarly knowledge. The methods that are relevant for producing knowledge are also relevant for evaluating knowledge. An example of a book that turns methodology upside-down and uses it to evaluate produced knowledge is Katzer; Cook & Crouch (1998). See also Unobtrusive measures, Triangulation (social science).

Science studies

Studies of quality evaluation processes such as peer review, book reviews and of the normative criteria used in evaluation of scientific and scholarly research. Another field is the study of Scientific misconduct.

Harris (1979) provides a case study of how a famous experiment in psychology, Little Albert, has been distorted throughout the history of psychology, starting with the author (Watson) himself, general textbook authors, behavior therapists, and a prominent learning theorist. Harris proposes possible causes for these distortions and analyzes the Albert study as an example of myth making in the history of psychology. Studies of this kind may be regarded a special kind of reception history (how Watson's paper was received). It may also be regarded as a kind of critical history (opposed to ceremonial history of psychology, cf. Harris, 1980). Such studies are important for source criticism in revealing the bias introduced by referring to classical studies.

See also Hjørland (2008): Empirical studies of the quality of science.

Textual criticism

Textual criticism (or broader: text philology) is a part of philology, which is not just devoted to the study of texts, but also to edit and produce "scientific editions", "scholarly editions", "standard editions", "historical editions", "reliable editions", "reliable texts", "text editions" or "critical editions", which are editions in which careful scholarship has been employed to ensure that the information contained within is as close to the author's/composer's original intentions as possible (and which allows the user to compare and judge changes in editions published under influence by the author/composer). The relation between these kinds of works and the concept "source criticism" is evident in Danish, where they may be termed "kildekritisk udgave" (directly translated "source critical edition").

In other words, it is assumed that most editions of a given works is filled with noise and errors provided by publishers, why it is important to produce "scholarly editions". The work provided by text philology is an important part of source criticism in the humanities.

• Palaeography
• Textual criticism
• Higher criticism
• Historical editions (music)
• Urtext edition

complete works and monumental editions

Psychology

The study of eyewitness testimony is an important field of study used, among other purposes, to evaluate testimony in courts. The basics of eyewitness fallibility includes factors such as poor viewing conditions, brief exposure, and stress. More subtle factors, such as expectations, biases, and personal stereotypes can intervene to create erroneous reports. Loftus (1996) discuss all such factors and also shows that eyewitness memory is chronically inaccurate in surprising ways. An ingenious series of experiments reveals that memory can be radically altered by the way an eyewitness is questioned after the fact. New memories can be implanted and old ones unconsciously altered under interrogation.

Anderson (1978) and Anderson & Pichert (1977) reported an elegant experiment demonstrating how change in perspective affected people's ability to recall information that was unrecallable from another perspective.

In psychoanalysis the concept of defence mechanism is important and may be considered a contribution to the theory of source criticism because it explains psychological mechanisms, which distort the reliability of human information sources.

Library and information science (LIS)

In schools of library and information science (LIS) is source criticism of taught as part of the growing field Information literacy. Study issues like relevance, quality indicators for documents, kinds of documents and their qualities (e.g. scholarly editions) and related issues are studied in LIS and are relevant for source criticism. Bibliometrics is often used to find the most influential journal, authors, countries and institutions. The study of book reviews and their function in evaluating books should also be mentioned. The well-known comparison of Wikipedia and Encyclopædia Britannica (Giles, 2005) - although not done by information scientists - contained an interview with an information scientist (Michael Twidale) and should be obvious to include in LIS.

It could be argued that library and information education should provide teaching in source criticism at least at the same level as is taught in Upper Secondary School (see Gudmundsson, 2007).

In library and information science the checklist approach has often been used.^[3] A criticism of this approach is given by Meola (2004): "Chucking the checklist".

Libraries sometimes provide advices on how their users may evaluate sources.^[4][5]

The Library of Congress has a "Teaching with Primary Sources" (TPS) program.^[6]

Ethics

Source criticism is also about ethical behavior and culture. It is about a free press and an open society, including the protecting information sources from being persecuted (cf., Whistleblower).

In specific domains

Photos

Photos are often manipulated during wars and for political purposes. One well known example is Joseph Stalin's manipulation of a photograph from May 5, 1920 on which Stalin's predecessor Lenin held a speech for Soviet troops that Leon Trotsky attended. Stalin had later Trotsky retouched out of this photograph. (cf. King, 1997). A recent example is reported by Healy (2008) about North Korean leader Kim Jong Il.^[7]

Internet sources

Much interest in evaluating Internet sources (such as Wikipedia) is reflected in the scholarly literature of Library and information science and in other fields. Mintz (2002) is an edited volume about this issue. Examples of literature examining Internet sources include Chesney (2006), Fritch & Cromwell (2001), Leth & Thurén (2000) and Wilkinson, Bennett, & Oliver (1997).

Archaeology and history

"In history, the term historical method was first introduced in a systematic way in the sixteenth century by Jean Bodin in his treatise of source criticism, Methodus ad facilem historiarium cognitionem (1566). Characteristically, Bodin's treatise intended to establish the ways by which reliable knowledge of the past could be established by checking sources against one another and by so assessing the reliability of the information conveyed by them, relating them to the interests involved." (Lorenz, 2001, p. 6870).

As written above, modern source criticism in history is closely associated with the German historian Leopold von Ranke (1795–1886), who influenced historical methods on both sides of the Atlantic Ocean, although in rather different ways. American history developed in a more empirist and antiphilosophical way (cf., Novick, 1988).

Two of the best-known rule books from History's childhood are Bernheim (1889) and Langlois & Seignobos (1898). These books provided a seven-step procedure (here quoted from Howell & Prevenier, 2001, p. 70-71):

1. If the sources all agree about an event, historians can consider the event proved.
2. However, majority does not rule; even if most sources relate events in one way, that version will not prevail unless it passes the test of critical textual analysis.
3. The source whose account can be confirmed by reference to outside authorities in some of its parts can be trusted in its entirety if it is impossible similarly to confirm the entire text.
4. When two sources disagree on a particular point, the historian will prefer the source with most "authority" - - i.e. the source created by the expert or by the eyewitness.
5. Eyewittnesses are, in general, to be preferred, especially in circumstances where the ordinary observer could have accurately reported what transpired and, more specifically, when they deal with facts known by most contemporaries.
6. If two independently created sources agree on a matter, the reliability of each is measureably enhanced.
7. When two sources disagree (and there is no other means of evaluation), then historians take the source which seems to accord best with common sense.

Gudmundsson (2007, p. 38) writes: ”Source criticism should not totally dominate later courses. Other important perspectives, for example, philosophy of history/view of history, should not suffer by being neglected” (Translated by BH). This quote makes a distinction between source criticism on the one hand and historical philosophy on the other hand. However, different views of history and different specific theories about the field being studied may have important consequences for how sources are selected, interpreted and used. Feminist scholars may, for example, select sources made by women and may interpret sources from a feminist perspective. Epistemology should thus be considered a part of source criticism. It is in particular related to "tendency analysis".

In archaeology, radiocarbon dating is an important technique to establish the age of information sources. Methods of this kind were the ideal when history established itself as both a scientific discipline and as a profession based on "scientific" principles in the last part of the 1880s (although radiocarbon dating is a more recent example of such methods). The empiricist movement in history brought along both "source criticism" as a research method and also in many countries large scale publishing efforts to make valid editions of "source materials" such as important letters and official documents (e.g. as facsimiles or transcriptions).

Historiography and Historical method include the study of the reliability of the sources used, in terms of, for example, authorship, credibility of the author, and the authenticity or corruption of the text.

Biblical studies

Source criticism, as the term is used in biblical criticism, refers to the attempt to establish the sources used by the author and/or redactor of the final text. The term "literary criticism" is occasionally used as a synonym.

Biblical source criticism originated in the 18th century with the work of Jean Astruc, who adapted the methods already developed for investigating the texts of Classical antiquity (Homer's Iliad in particular) to his own investigation into the sources of the Book of Genesis. It was subsequently considerably developed by German scholars in what was known as "the Higher Criticism", a term no longer in widespread use. The ultimate aim of these scholars was to reconstruct the history of the biblical text, as well as the religious history of ancient Israel.

Related to Source Criticism is Redaction Criticism which seeks to determine how and why the redactor (editor) put the sources together the way he did. Also related is form criticism and tradition history which try to reconstruct the oral prehistory behind the identified written sources.

Journalism

Journalists often work with strong time pressure and have access to only a limited number of information sources such as news bureaus, persons which may be interviewed, newspapers, journals and so on (see journalism sourcing). Journalists' possibility for conducting serious source criticism is thus limited compared to, for example, historians' possibilities.

Legal studies

The most important legal sources are created by parliaments, governments, courts, and legal researchers. They may be written or informal and based on established practices. Views concerning the quality of sources differ among legal philosophies: Legal positivism is the view that the text of the law should be considered in isolation, while legal realism, interpretivism (legal), critical legal studies and feminist legal criticism interprets the law on a broader cultural basis.

See also

Notes

References

• American Library Association (1994) Evaluating Information: A Basic Checklist. Brochure. American Library Association
• Anderson, Richard C. (1978). Schema-directed processes in language comprehension. IN: NATO International Conference on Cognitive Psychology and Instruction, 1977, Amsterdam: Cognitive Psychology and Instruction. Ed. by A. M. Lesgold, J. W. Pellegrino, S. D. Fokkema & R. Glaser. New York: Plenum Press (pp. 67–82).
• Anderson, Richard C. & Pichert, J. W. (1977). Recall of previously unrecallable information following a shift of perspective. Urbana, Il: University of Illinois, Center for the Study of Reading, April. 1977. (Technical Report 41). Available in full-text from: http://eric.ed.gov/ERICDocs/data/ericdocs2sql/content_storage_01/0000019b/80/31/83/58.pdf
• Bazerman, Charles (1995). The Informed Writer: Using Sources in the Disciplines. 5th ed. Houghton Mifflin.
• Bee, Ronald E. (1983). Statistics and Source Criticism. Vetus Testamentum, Volume 33, Number 4, 483–488.
• Beecher-Monas, Erica (2007). Evaluating scientific evidence : an interdisciplinary framework for intellectual due process. Cambridge; New York: Cambridge University Press.
• Bernheim, Ernst (1889). Lehrbuch der Historischen Methode und der Geschichtsphilosophie [Guidebook for Historical Method and the Philosophy of History]. Leipzig: Duncker & Humblot.
• Brundage, Anthony (2007). Going to the Sources: A Guide to Historical Research and Writing, 4th Ed. Wheeling, Illinois: Harlan Davidson, Inc. (3rd edition, 1989 cited in text above).
• Chesney, T. (2006). An empirical examination of Wikipedia’s credibility. First Monday, 11(11), URL: http://firstmonday.org/issues/issue11_11/chesney/index.html
• Encyclopædia Britannica (2006). Fatally Flawed. Refuting the recent study on encyclopedic accuracy by the journal Nature. http://corporate.britannica.com/britannica_nature_response.pdf Nature's response March 23, 2006: http://www.nature.com/press_releases/Britannica_response.pdf
• Engeldinger, Eugene A. (1988) Bibliographic Instruction and Critical Thinking: The Contribution of the Annotated Bibliography. Research Quarterly, Vol. 28, Winter, p. 195-202
• Engeldinger, Eugene A. (1998) Technology Infrastructure and Information Literacy. Library Philosophy and Practice Vol. 1, No. 1
• Fritch, J. W., & Cromwell, R. L. (2001). Evaluating Internet resources: Identity, affiliation, and cognitive authority in a networked world. Journal of the American Society for Information Science and Technology, 52, 499–507.
• Gerhart, Susan L. (2004). Do Web search engines suppress controversy?. First Monday 9(1).
• Giles, J. (2005). Special Report: Internet encyclopaedias go head to head. Nature, 438, 900–901. Available: http://www.nature.com/nature/journal/v438/n7070/full/438900a.html Supplementary information: http://www.nature.com/nature/journal/v438/n7070/extref/438900a-s1.doc
• Gudmundsson, David (2007). När kritiska elever är målet. Att undervisa i källkritik på gymnasiet. [When the Goal is Critical Students. Teaching Source Criticism in Upper Secondary School]. Malmö, Sweden: Malmö högskola. Full text (Swedish)
• Hardtwig, W. (2001). Ranke, Leopold von (1795–1886). IN: Smelser, N. J. & Baltes, P. B. (eds.) International Encyclopedia of the Social and Behavioral Sciences. Amsterdam: Elsevier. (12738–12741).
• Harris, Ben (1979). Whatever Happened to Little Albert? American Psychologist, 34, 2, pp. 151–160. link to full text
• Harris, Ben (1980). Ceremonial versus critical history of psychology. American Psychologist, 35(2), 218–219. (Note).
• Healy, Jack (2008). Was the Dear Leader Photoshopped In? November 7, 2008, 2:57 pm [President Kim Jong Il, North Korea]. http://thelede.blogs.nytimes.com/2008/11/07/was-the-dear-leader-photoshopped-in/?scp=7&sq=Kim%20Jong-il&st=cse
• Hjørland, Birger (2008). Source criticism. In: Epistemological Lifeboat. Ed. by Birger Hjørland & Jeppe Nicolaisen.
• Howell, Martha & Prevenier, Walter (2001). From Reliable Sources: An Introduction to Historical Methods. Ithaca: Cornell University Press. ISBN 0-8014-8560-6.
• Katzer, Jeffrey; Cook, Kenneth H. & Crouch, Wayne W. (1998). Evaluating Information: A Guide for Users of Social Science Research. 4th ed. Boston, MA: McGraw-Hill.
• King, David (1997) The Commissar Vanishes: the falsification of photographs and art in Stalin's Russia. Metropolitan Books, New York.
• Langlois, Charles-Victor & Seignobos, Charles (1898). Introduction aux études historiques [Introduction to the Study of History]. Paris: Librairie Hachette. Full text (French). Introduction to the Study of History Full text (English)
• Leth, Göran & Thurén, Torsten (2000). Källkritik för internet . Stockholm: Styrelsen för Psykologiskt Försvar. (Hentet 2007-11-30).
• Loftus, Elizabeth F. (1996). Eyewitness Testimony. Revised edition Cambridge, MA: Harward University Press. (Original edition:1979).
• Lorenz, C. (2001). History: Theories and Methods. IN: Smelser, N. J. & Baltes, P. B. (eds.) International Encyclopedia of the Social and Behavioral Sciences. Amsterdam: Elsevier. (Pp. 6869–6876).
• Mathewson, Daniel B. (2002). A critical binarism: Source criticism and deconstructive criticism. Journal for the study of the Old Testament no98, pp. 3–28. Abstract: When classifying the array of interpretive methods currently available, biblical critics regularly distinguish between historical-critical methods, on the one hand, and literary critical methods, on the other. Frequently, methods on one side of the divide are said to be antagonistic to certain methods on the other. This article examines two such presumed antagonistic methods, source criticism and deconstructive criticism, and argues that they are not, in fact, antagonistic, but similar: both are postmodern movements, and both share an interpretive methodology (insofar as it is correct to speak of a deconstructive methodology). This argument is illustrated with a source-critical and a deconstructive reading of Exodus 14.
• Mattus, Maria (2007). Finding Credible Information: A Challenge to Students Writing Academic Essays. Human IT 9(2), 1–28. Hentet 2007-09-04 fra: http://www.hb.se/bhs/ith/2-9/mm.pdf
• Meola, M (2004). Chucking the checklist: A contextual approach to teaching undergraduates web-site evaluation. Portal: Libraries and the Academy, 4(3), 331-344. Downloaded 2008-10-23 from: http://muse.jhu.edu/journals/portal_libraries_and_the_academy/v004/4.3meola.pdf
• Mintz, Anne P. (ed.). (2002). Web of deception. Misinformation on the Internet. Medford, NJ: Information Today.
• Müller, Philipp (2009). Understanding history: Hermeneutics and source-criticism in historical scholarship. IN: Dobson, Miriam & Ziemann, Benjamin (eds): Reading primary sources. The interpretation of texts from nineteenth and twentieth-century history. London: Routledge (pp. 21–36).
• Olden-Jørgensen, Sebastian (2001). Til Kilderne: Introduktion til Historisk Kildekritik (in Danish). [To the sources: Introduction to historical source criticism]. København: Gads Forlag. ISBN 978-87-12-03778-1.
• Reinfandt, Christohp (2009). Reading texts after the linguistic tturn: approaches from literary studies and their implementation. IN: Dobson, Miriam & Ziemann, Benjamin (eds): Reading primary sources. The interpretation of texts from nineteenth and twentieth-century history. London: Routledge (pp. 37–54).
• Rieh, S. Y. (2002). Judgment of information quality and cognitive authority in the Web. Journal of the American Society for Information Science and Technology, 53(2), 145–161. http://www.si.umich.edu/rieh/papers/rieh%5Fjasist2002.pdf
• Rieh, S. Y. (2005). Cognitive authority. I: K. E. Fisher, S. Erdelez, & E. F. McKechnie (Eds.), Theories of information behavior: A researchers' guide . Medford, NJ: Information Today (pp. 83–87). http://newweb2.si.umich.edu/rieh/papers/rieh%5FIBTheory.pdf
• Rieh, Soo Young & Danielson, David R. (2007). Credibility: A multidisciplinary framework. Annual Review of Information Science and Technology, 41, 307–364.
• Riegelman, Richard K. (2004). Studying a Study and Testing a Test: How to Read the Medical Evidence. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins.
• Savolainen, R. (2007). Media credibility and cognitive authority. The case of seeking orienting information. Information Research, 12(3) paper 319. Available at http://InformationR.net/ir/12-3/paper319.html
• Slife, Brent D. & Williams, R. N. (1995). What's behind the research? Discovering hidden assumptions in the behavioral sciences. Thousand Oaks, CA: Sage Publications. ("A Consumers Guide to the Behavioral Sciences").
• Taylor, John (1991). War photography; realism in the British press. London : Routledge.
• Thurén, Torsten. (1997). Källkritik. Stockholm: Almqvist & Wiksell.
• Walton, Douglas (1998). Fallacies. IN: Routledge Encyclopedia of Philosophy, Version 1.0, London: Routledge
• Webb, E J; Campbell, D T; Schwartz, R D & Sechrest, L (2000). Unobtrusive measures; revised edition. Sage Publications Inc.
• "Wikipedia: Testsieg und Verschwörungen" [Sterns test of Wikipedia]. Heise Online (in German). 5 December 2007. 
• Wilkinson, G.L., Bennett, L.T., & Oliver, K.M. (1997). Evaluation criteria and indicators of quality for Internet resources. Educational Technology , 37(3), 52–59.
• Wilson, Patrick (1983). Second-Hand Knowledge. An Inquiry into Cognitive Authority. Westport, Conn.: Greenwood.

External links

• The Source Compass: Source Criticism
• The History Sourcebook: The Need for Source Criticism

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