The first article summarizes the findings of four studies which used unobtrusive testing techniques to evaluate library reference services. The validity of this testing method and the conclusions reached are discussed, and suggestions are made for improving reference services in five related articles. (CLB)

Discusses issues relating to the reliability, validity, utility, and information value of unobtrusive testing of library reference services; provides suggestions for practical applications of these criteria; applies study findings to library decision making and planning; and identifies topics for further methodological refinement. (Author/CLB)