CRANV1P1 Indexing Procedures chapter Cyril Cleverdon Jack Mills Michael Keen Cranfield An investigation supported by a grant to Aslib by the National Science Foundation. Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. -43 - Titanium on the other would make it clear which property referred to which substance. Clearly, a link must involve at least two terms. (iv) Roles - i.e. , indicating the role or function of a particular term in an indexing description. Sometimes a simple link is insufficient to remove ambiguity; e.g., Production of particle x by bombardment of particle [OCRerr]. To link, say, Production with x and Bombardment with y could still allow the description to be interpreted a[OCRerr] Production by x, or Bombardment of y. The addition of a role-indicator makes the relationship more explicit, e.g. by labelling x as Product and y us Patient (and possibly a bombarding particle, z, as Agent). Devices which increase recall (v) Confounding synonyms - i.e., accepting items indexed by x when searching for y, and vice-versa, where x and y are regarded as synonymous. (vi) Confounding word forms - i. e., accepting items indexed by different forms of the search terms, such as its singular and plural, participle and gerund; e.g., Injectant + Injected + Injection + Injectors. The most comprehensive operation of this device is where a stem or root is used to define the class and all words con- taining it are included in the class (vii) Hierarchical linkage - i. e., accepting items indexed by terms which are in some generic hierarchical relation to the search term. By this we mean terms which are either subordinate to, superordinate to, coordinate with, or collateral with the search term; e.g., the class Cooling might be extended hierarchically to include the subor- dinate term Sweat cooling, the superordinate term Heat transfer, the coordinate term Heating and the collateral term Radiation. This is a stricter interpretation of hierarchical linkage than is often used in the literature of IR0 confining it to the relations between a thing and its kinds as distinct from numerous other relations such as those between a thing and its parts, its processes, its properties, the opera- tions performed on it, and so on. It is perhaps necessary to note that hierarchical linkage is essentially a recall device. This is not to say that it cannot be used in order to refine a question and give it more precision; e g., an enquirer about to search the class Cooling might be led to realise (by the hierarchical display of related terms) that he really wanted Sweat cooling and would then narrow his search by confining it to this species of cooling. This is almost as though hierarchical linkage were acting as a precision device. But clearly, the question asked was wrongly put and the function of the hierarchy would have been to assist the question- programmir[OCRerr]g. In testing devices it must be assumed that the question has been accurately stated, otherwise a large and disrupting variable will enter the test. Therefore such adjustments as the one described cannot be considered, and hierarchical linkage must be treated as a recall device only. (viii) Non-generic hierarchical linkage. The device of hierarchical linkage which has always featured prominently in subject indexing and is the central device in what is generally known as 'classification, is the result of selecting one particular relation- ship (the generic one, between a thing and its kinds) as the basis of various kinds of class definition. This raises the question: should we similarly regard the use of other particular relations (e. g. , between a thing and its parts, a thing and its pro- perties) as constituting separate indexing devices, each to be evaluated separately?