The third volume of this five volume study of the INSPEC SDI system contains: Recall performance of SDI profiles; Assessment of the Recall performance of the SDI system in relation to particularly valuable articles; Subjective assessment of the SDI system Recall performance; Relation between Precision performance of the system and document indexing; User assessment of the SDI service; Relationship between quality of user's initial statement of information requirements and the subsequent assessment of his profile; Effect of profile analysis and modifications on user's satisfaction with service; Effect of number of document notifications received by user on his relevance assessment; Comparison of relevance assessments based on the full document with those based on card notifications giving varying amounts of document information; Effect of including author names as search terms in SDI profiles; Variation of user satisfaction with compiler of profile; Methods of user interaction in profile compilation; Use made of SDI notifications; Desirability of including material other than English-language periodical articles in the coverage of the SDI service; and Novelty of information provided by the SDI service. (Volumes I and II are: LI004067 and 004068, Volume IV and V are: LI004070 and 004071.) (Author/NH)