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The XML Version of the TEI Guidelines17 Certainty and Responsibility |
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17 Certainty and Responsibility 17.2 Attribution of Responsibility Introductory Note (March 2002) 2 A Gentle Introduction to XML 3 Structure of the TEI Document Type Definition 4 Languages and Character Sets 6 Elements Available in All TEI Documents 14 Linking, Segmentation, and Alignment 17 Certainty and Responsibility 18 Transcription of Primary Sources 21 Graphs, Networks, and Trees 22 Tables, Formulae, and Graphics 29 Modifying and Customizing the TEI DTD 32 Algorithm for Recognizing Canonical References 38 Sample Tag Set Documentation 39 Formal Grammar for the TEI-Interchange-Format Subset of SGML |
Encoders of text often find it useful to indicate that some aspects of the encoded text are problematic or uncertain, and to indicate who is responsible for various aspects of the markup of the electronic text. These Guidelines provide three methods of recording uncertainty about the text or its markup:
There are three methods of indicating responsibility for different aspects of the electronic text:
<!DOCTYPE TEI.2 PUBLIC "-//TEI P4//DTD Main Document Type//EN" "tei2.dtd" [ <!ENTITY % TEI.XML 'INCLUDE' > <!ENTITY % TEI.prose 'INCLUDE' > <!ENTITY % TEI.certainty 'INCLUDE' > ]> 17.1 Levels of CertaintyMany types of uncertainty may be distinguished. The <certainty> element is designed to encode the following sorts:
The following types of uncertainty are not indicated with the <certainty> element:
Precision of numbers and dates is discussed in section 6.4 Names, Numbers, Dates, Abbreviations, and Addresses; well-defined ambiguity is handled with alternations in feature-structure values in chapter 16 Feature Structures. Uncertainty about the truth of assertions in the text and other sorts of authorial and editorial uncertainty about whether the content is satisfactory are not handled by the <certainty> element, though they may be expressed using the <note> element. 17.1.1 Using Notes to Record UncertaintyThe simplest way of recording uncertainty about markup is to attach a note to the element or location about which one is unsure. In the following (invented) paragraph, for example, an encoder might be uncertain whether to mark ‘Essex’ as a place name or a personal name, since both might be plausible in the given context: Elizabeth went to Essex. She had always liked Essex.Using <note>, the uncertainty here may be recorded quite simply: <persName>Elizabeth</persName> went to <placeName>Essex</placeName>. She had always liked <placeName>Essex</placeName>.<note type="uncertainty" resp="MSM">It is not clear here whether <mentioned>Essex</mentioned> refers to the place or to the nobleman. -MSM</note> Using the normal mechanisms, the note may be associated unambiguously with specific elements of the text, thus: <persName>Elizabeth</persName> went to <placeName id="p1">Essex</placeName>. She had always liked <placeName id="p2">Essex</placeName>.<note type="uncertainty" resp="MSM" target="p1 p2">It is not clear here whether <mentioned>Essex</mentioned> refers to the place or to the nobleman. If the latter, it should be tagged as a personal name. -MSM</note> The advantage of this technique is its relative simplicity. Its disadvantage is that the nature and degree of uncertainty are not conveyed in any systematic way and thus are not susceptible to any sort of automatic processing. 17.1.2 Structured Indications of UncertaintyTo record uncertainty in a more structured way, susceptible of at least simple automatic processing, the <certainty> element may be used:
Returning to the example, the <certainty> element may be used to record doubts about the proper encoding of ‘Essex’ in several ways of varying precision. To record merely that we are not certain that ‘Essex’ is in fact a place name, as it is tagged, we use the target attribute to identify the element in question, and the locus attribute to indicate what aspect of the markup we are uncertain about (in this case, whether we have used the correct element type): Elizabeth went to <placeName id="p1">Essex</placeName>. <!-- ... elsewhere in the document ... --> <certainty target="p1" locus="#gi" desc="possibly not a placename"/>Because it is linked to the location of the uncertainty by a reference, the <certainty> element will typically be included in the same document as its target. It may be placed adjacent to the target element, or elsewhere in the document. To record the further information that we estimate, subjectively, that there is a 60 percent chance of ‘Essex’ being a place name here, we can add a value for our degree of confidence (usually a number between 0 and 1, representing the estimated probability): Elizabeth went to <placeName id="p1">Essex</placeName>. <!-- ... --> <certainty target="p1" locus="#gi" desc="possibly not a placename" degree="0.6"/>According to one expert, there is a 60 percent chance of ‘Essex’ being a place name here, and a 40 percent chance of its being a personal name. We use two <certainty> elements to indicate the two probabilities independently. Both elements indicate the same location in the text, but the second provides an alternative choice of generic identifier (in this case <persName>) is given as the value of the assertedValue attribute: Elizabeth went to <placeName id="p1">Essex</placeName>. <!-- ... --> <certainty target="p1" locus="#gi" desc="probably a placename, but possibly not" degree="0.6"/> <certainty target="p1" locus="#gi" assertedValue="persName" desc="may refer to the Earl of Essex" degree="0.4"/> Finally, we may wish to make our probability estimates contingent on some condition. In the passage ‘Elizabeth went to Essex; she had always liked Essex,’ for example, we may feel there is a 60 percent chance that the county is meant, and a 40 percent chance that the earl is meant. But the two occurrences of the word are not independent: there is (we may feel) no chance at all that one occurrence refers to the county and one to the earl. We can express this by using the given attribute to list the identifiers of <certainty> elements. Elizabeth went to <placeName id="p1">Essex</placeName>. She had always liked <placeName id="p2">Essex</placeName>. <!-- ... --> <!-- 60% chance that P1 is a placename, 40% chance a personal name. --> <certainty id="cert-1" target="p1" locus="#gi" desc="probably a placename, but possibly not" degree="0.6"/> <certainty id="cert-2" target="p1" locus="#gi" desc="may refer to the Earl of Essex" assertedValue="persName" degree="0.4"/> <!-- 60% chance that P2 is a placename, 40% chance a personal name. 100% chance that it agrees with P1. --> <certainty target="p2" locus="#gi" given="cert-1" desc="if P1 is a placename, P2 certainly is" degree="1.0"/> <certainty target="p2" locus="#gi" assertedValue="persName" given="cert-2" desc="if p1 refers to the Earl of Essex, so does P2" degree="1.0"/>When given conditions are listed, the <certainty> element is interpreted as claiming a given degree of confidence in a particular markup given the assertional content of the <certainty> elements indicated—that is, if the markup described in the indicated <certainty> elements is correct. Conditional confidence may be less that 100 percent: given the sentence ‘Ernest went to old Saybrook’, we may interpret ‘Saybrook’ as a personal name or a place name, assigning a 60 percent probability to the former. If it is a place name, there may be a 50 percent chance that the place name actually in question is ‘Old Saybrook’ rather than ‘Saybrook’, while if it is correctly tagged as a personal name, it is much more likely (say, 90 percent certain) that the name is ‘Saybrook’. This state of affairs can be expressed using the <certainty> element thus: Earnest went to <anchor id="a1"/> old <persName id="p1">Saybrook</persName>. <certainty id="c1" target="p1" locus="#gi" degree="0.6"/> <certainty target="p1" locus="startloc" given="c1" degree="0.9"/> <certainty id="c2" target="p1" locus="#gi" assertedValue="persName" degree="0.4"/> <certainty target="p1" locus="startloc" given="c2" degree="0.5"/> <certainty id="c3" target="p1" locus="startloc" assertedValue="a1" given="c1" degree="0.5"/>In this case, the assertedValue on <certainty> element c3 is a reference to an <anchor> element at the alternative starting point for the element. Multiplying the numeric values out, this markup may be interpreted as assigning specific probabilities to three different ways of marking up the sentence: Earnest went to old <persName>Saybrook</persName>. (0.6 * 0.9, or 0.54) Earnest went to old <placeName>Saybrook</placeName>. (0.4 * 0.5, or 0.20) Earnest went to <placeName>old Saybrook</placeName>. (0.4 * 0.5, or 0.20)The probabilities do not add up to 1.00 because the markup indicates that if ‘Saybrook’ is (part of) a personal name, there is a 10 percent likelihood that the element should start somewhere other than the place indicated, without however giving an alternative location; there is thus a 6 percent chance (0.1 × 0.6) that none of the alternatives given is correct. If an attribute value is uncertain, the locus attribute takes as its value the name of the attribute in question. In this example, there is only a 50 percent chance that the question was spoken by participant A: <u id="u1" who="a">Have you heard the election results?</u> <!-- ... --> <certainty target="u1" locus="who" degree="0.5"/> Doubts about whether the transcription is correct may be expressed by assigning to locus the value ‘#transcribedContent’. For example, if the source is hard to read and so the transcription is uncertain: I have a <emph id="p1">gub</emph>. <certainty target="p1" locus="#transcribedContent" degree="0.5"/> Degrees of confidence in the proper expansion of abbreviations may also be expressed, by using the value ‘#suppliedContent’: You will want to use <expan id="e1" abbr="SGML">Standard Generalized Markup Language</expan> ... <!-- ... --> <certainty target="e1" locus="#suppliedContent" degree="0.9"/> The assertedValue attribute should be used to provide an alternative value for whatever aspect of the markup is in doubt: an alternative generic identifier, or the identifier of an alternative starting or ending point, as already shown, an alternative attribute value, or alternative element content, as in this example: I have a <emph id="p1">gub</emph>. <certainty target="p1" locus="#transcribedContent" assertedValue="gun" desc="a gun makes more sense in a holdup" degree="0.8"/>Since attribute values have no internal substructure, the assertedValue attribute is useful for specifying alternative transcriptions only in relatively restricted circumstances (specifically, when the alternative reading has no elements nested within it). More robust methods of handling uncertainties of transcription are the <unclear> element and the <app> and <rdg> elements described in chapter 19 Critical Apparatus. The <certainty> element allows for indications of uncertainty to be structured with at least as much detail and clarity as appears to be currently required in most ongoing text projects. It is expected that in the future more adequate systems for expressing uncertainty will be developed. These may extend the <certainty> element or they may make use of the feature-structure encoding mechanisms described in chapter 16 Feature Structures. The <certainty> element and the other TEI mechanisms for indicating uncertainty provide a range of methods of graduated complexity. Simple expressions of uncertainty may be made by using the <note> element. This is simple and convenient, and can accommodate either a discursive and unstructured indication of uncertainty, or a complex and structured but probably project-specific expression of uncertainty. In general, however, unless special steps are taken, the <note> element does not provide as much expressive power as the <certainty> element, and in cases where highly structured certainty information must be given, it is recommended that the <certainty> element be used. The <certainty> element may be used for simple unqualified indications of uncertainty, in which case only the locus and target attributes might be specified. In more complex cases, the other attributes may be used to provide fuller information. While these attributes may take any string of characters as value, the recommended values should be used wherever possible; if they are not appropriate in a given situation, encoders should provide their own controlled vocabulary and document it in the <encodingDesc> or <tagUsage> elements of the TEI header. The <certainty> element has the following formal declaration: <!-- 17.1.2: Certainty and uncertainty--> <!--Text Encoding Initiative Consortium: Guidelines for Electronic Text Encoding and Interchange. Document TEI P4, 2002. Copyright (c) 2002 TEI Consortium. Permission to copy in any form is granted, provided this notice is included in all copies. These materials may not be altered; modifications to these DTDs should be performed only as specified by the Guidelines, for example in the chapter entitled 'Modifying the TEI DTD' These materials are subject to revision by the TEI Consortium. Current versions are available from the Consortium website at http://www.tei-c.org--> <!ELEMENT certainty %om.RO; EMPTY> <!ATTLIST certainty %a.global; target IDREFS #REQUIRED locus CDATA #REQUIRED assertedValue CDATA #IMPLIED desc CDATA #IMPLIED given CDATA #IMPLIED degree CDATA #IMPLIED TEIform CDATA 'certainty' > [declarations from 17.2: Responsibility for markup inserted here ] <!-- end of 17.1.2--> 17.2 Attribution of ResponsibilityIn general, attribution of responsibility for the transcription and markup of an electronic text is made by <respStmt> elements within the header: specifically, within the title statement, the edition statement(s), and the revision history. In some cases, however, more detailed element-by-element information may be desired. For example, an encoder may wish to distinguish between the individuals responsible for transcribing the content and those responsible for determining that a given word or phrase constitutes a proper noun. Where such fine-grained attribution of responsibility is required, the <respons> element can be used:
This element allows one or more aspects of the markup to be attributed to a given individual. The target and locus attributes function as they do on the <certainty> element described in section 17.1 Levels of Certainty: the target attribute points at a particular element (or set of elements), and locus indicates the particular aspect of the encoding of those elements for which responsibility is to be assigned. The suggested values may be combined as appropriate. For example, to indicate that RC is responsible for transcribing an illegible word, and that AR is responsible for identifying that word as a proper noun, the text might be encoded thus: Earnest went to old <persName id="p1">Saybrook</persName>. <!-- ... --> <respons target="p1" locus="#transcribedContent" resp="RC"/> <respons target="p1" locus="#gi #location" resp="AR"/> Some elements bear specialized resp or agent attributes, which have specific meanings that vary from element to element; the <respons> element should be reserved for the general aspects of responsibility common to all text transcription and markup, and should not be confused with the more specific attributes on individual elements. The formal declaration of the <respons> element is this: <!-- 17.2: Responsibility for markup--> <!ELEMENT respons %om.RO; EMPTY> <!ATTLIST respons %a.global; target IDREFS #REQUIRED locus CDATA #REQUIRED resp CDATA #REQUIRED desc CDATA #IMPLIED TEIform CDATA 'respons' > <!-- end of 17.2--> |
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