If You Want to Evaluate Your Library--

Lancaster's book is excellent and highly recommended for anyone in library & information science. It is clearly written and easy to understand while still rigorous and based on evidence.

My impression is that this book is clear in its explanations, but also it gives a clear idea on the 80/20 rule. Furthermore, it amazes librarians explaining them how a library and library science can be focused on the basis of bussiness administration. I have used it to teach my pupils at the Universidad del Museo Social Argentino, library statistics and translated them the valuable principles of Ranganhatan. In some respects these books has treated in advance the subject of 80/20 rule first the Richar Koch who has devoted a whole book on this topic.