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Welcome to the Chartmasters website. This site is dedicated to popular music and the popularity rankings of songs detailed in the Chartmasters’ publication ROCK 100.

The authors of ROCK 100, Jim Quirin and Barry Cohen, added a new dimension to popular music rankings with their development of the Cumulative Popularity Index, or CPI, in 1974. Though many people have utilized simplified ranking techniques for years, Jim and Barry combined their knowledge of the record charts with the application of the principles of mathematics to develop the most sophisticated and accurate methodology available today.

Their mathematical algorithm and its development have been included (by permission) in numerous mathematics textbooks, demonstrating the soundness of the authors’ theories and the practical application of the basic principles of calculus.


All Billlboard® chart data which appears in our publications and on this site is Copyright © by Billboard Publications, Inc. and used by permission.

About our Company

Chartmasters was founded in August of 1975 by Jim Quirin and Barry Cohen, who met on the campus of the University of Illinois while working on graduate degrees in Electrical Engineering and Mathematics respectively.

Jim and Barry immediately discovered that they both shared common interests in popular music and record charts. They spent four years of combined research in analyzing record charts and the dynamics of individual recording movements on those charts. They collected data and plotted graphs representing record performance to develop a complete understanding of song movement on the music charts. Their research culminated in the release of the First Edition of ROCK 100, covering the years 1956 through 1974. 

To promote their new book, Quirin and Cohen teamed up with personnel at local radio station WLRW in Champaign-Urbana to put together the "Rock Of Ages" radio program. This 19-week special used a countdown format interspersed with musical trivia about artists, songwriters, producers, etc. to play the Top 100 songs for a selected year on Saturday of each week. Most of the music came from Jim Quirin’s extensive collection of 45 rpm singles, and most of the music trivia from Barry Cohen’s knowledge of music performers. In addition, Barry’s wife Karla collected interesting facts about key events of the featured year for that week. The WLRW audience during the "Rock Of Ages" show was the largest the station had ever reached at that time.  

The success of ROCK 100 led to the release of the Second Edition in 1976, the Third Edition in 1982, the Fourth Edition in 1987, and the Fifth Edition in 1992. Chartmasters has delivered its products to all 50 states, and to most major countries in the world. Their research continues today on music charts from 1948 to 1999.

About the Authors

Jim Quirin holds Bachelor’s and Master’s Degrees in Electrical Engineering from the University of Illinois, and is retired from the  Lockheed Martin Corporation where he was employed for 29 years as a senior staff design engineer in the Space Shuttle Program. He worked at NASA’s Michoud Assembly Facility in New Orleans where the External Fuel Tank for the Space Shuttle was manufactured and assembled .

Jim’s interest in popular music and rankings dates back to his early youth in Smithton, Illinois, where he collected feedback from neighborhood friends to produce typewritten rankings of their particular favorites. This interest continued into high school, where he started his extensive personal collection of 45 rpm singles. His collection provided much of the musical material for the "Rock Of Ages" weekly radio show in 1975.

  Dr. Barry Cohen holds a Bachelor of Arts Degree in Mathematics from UCLA, and a Ph.D. in Mathematics from the University Of Illinois. Barry is a leading expert in the field of interactive multimedia, with over 25 years of experience. He is credited with producing the first commercially successful interactive multimedia training course, and currently runs his own consulting business.

He has been following the popular music scene from the days when he listened to the original TV countdown of pop music hits, "Your Hit Parade." In 1975, he joined forces with Jim Quirin to found Chartmasters, publish ROCK 100, and produce WLRW's "Rock Of Ages" radio program.













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