14.2 Disadvantages of ISI's Web of Science
ISI's disadvantages also mirror Google Scholar's advantages. It is fairly expensive (my university pays around $120,000/year for its yearly subscription to the Web of Knowledge) and hence only available to academics working at relatively well-resourced universities. Its user interface is fairly cumbersome and tends to be slow, much slower than Google Scholar.
However, ISI's most important disadvantage lies in its lack of comprehensive coverage in some disciplines, resulting in an underestimation of citation impact. I will discuss this in more detail in Section 14.2.1. In addition, ISI has a number of idiosyncrasies that are discussed in later sections: its difficulty in reliably establishing self-citations (Section 14.2.2), its poor handling of stray citations (Section 14.2.3), and its frequent misclassification of original research articles as review articles and proceedings articles (Section 14.2.4).