Introduction: Reference sources are the backbone of a library. It helps the libraries and librarian in maintaining the question banks from which answer to queries of the users and material required by users are available. It may be added that the border line of demarcation between a reference book and others is not always sharp. The decisions as to whether or not to regard a given book as a reference book will sometime different from library to library.
The checklists for evaluation of reference sources are more or less same for all types of work. They can be applied to all sources with slight modification. The mnemonic form APPARATUS can be used as a check points for their appraisal. The APPARATUS indicates:
P- Purpose, Price
P- Physical format, Picture
R- Receney, Revision
Authority: The work should be authoritative. The authoritiveness of a reference book can usually be judge on the basis of qualification, experience and reputation of the sponsoring body (if any), publisher, distributor, author(s), Editor(s), Compiler(s).
Purpose, Price: What is the purpose of the work as stated by the editor himself? Has this purpose been full field in the main work? What is the total cost of the work and whether the cost can be justified on the basis of its content?
Physical Format, Picture: It refers to the physical make up of the book. All reference works should be a handy volume easy to withstand wear and tear. Format refers to binding quality of paper, typefaces, page make up, illustration, plates, diagrams, maps etc. Binding is of special consideration for bulky works likely to be used heavily. Type face should be clear and legible with suitable headings and subheading in bold types for the guidance of the readers.
Arrangement: A reference sources demand easy and quick location of recorded entries. Goods arrangement adds to the value of a reference sources. The information must be systematically arranged. It is essential to have a detailed index which should provide for various kinds of approaches. The arrangement of the main text can be classified or chronological or geographic or alphabetical or some other. The kind of arrangement used should have a sound basis. Index to the main text is extremely important. The index should be detailed one providing reasonable number of approaches complemented by cross references. The index can be alphabetical or classified or some other.
Receney, Revision: Information is always developing, some old becomes obsolete and some new are added. So in the evaluation process, the evaluator should keep it in mind to check whether the work is current and update or not. A continuous revision policy must be followed. Some works may issue supplements containing new information. What devices it uses to keep the bibliographies up to date. Though some reference sources may contain some retrospective information, every year it should be thoroughly revised and updated. The time lag is important for current sources.
Accuracy: The work should be judged by the accuracy of the facts mentioned in the work.
Treatment: It is to be ascertained whether the information is reliable and accurate or not, whether the treatment is biased or unbiased. It includes how through, reliable and complete is the information e.g. Facts, statistics, place, names, names of persons, names of organization, bibliography whichever is applicable. Treatment should also include questions like does it show any bias on controversial topics. Has the space allocated for a topic related to the degree of importance attached to a topic? Has the work written for scholars or layman, adults or children? How readable is the writing etc.
Use: If the work will be purchased then who will be the user, who will benefit from the work. Does the library have such kind of user base or not?
Scope: The kind of information included would depend upon the scope of the work. Some work may cover a particular country or the whole world or all subjects while others may be restricted to some specific or minute topic only. The date or period covered is an important criterion. Sometimes it may relate to a particular subject, organization also. The content page, preface, and introduction may give an idea of the information contained in the work. What are the limitations of the reference work with regard to subject, class of reader, up- to-dateness of material, what is the overall coverage? Does it follow a definite plan consistently? What is the extent of supervision provided by the editor(s)?
Some works have a long history. It would be useful to add history as an additional check point
Overall Judgment: The evaluated reference sources are useful for what kind of library.