At an early age, we are introduced to performance measures: gold stars meant our parents were pleased with our behavior, schools use the letters A–D to denote a passing grade and F for failure, numerical grades can reflect academic performance over time, the grade point average of a high school senior can be compared with those of graduates of the same or different schools, and the Pharmacy College Admission Test score helps identify qualified applicants to pharmacy colleges.
The use of a single statistic to represent performance, achievement, or some other valued attribute is common. For example, lightbulbs are compared with a single number to predict their life span, and the industrial output of a nation can be summarized by a single statistic called the gross national product. Each of these statistics can be criticized but represent a useful measure of perceived worth.
Scientific journals are also evaluated by statistical methods. The impact factor (IF) is widely accepted as reflecting a journal’s value to the academic community it serves. It is determined using data on the total number of citations that occurred in a single year from articles that appeared in that journal during a previous 2-year period. Pharmacotherapy's current IF of 2.662 for 2014, the last year for which the IF is available, was calculated as the total number of times any article published in Pharmacotherapy in 2012 or 2013 was cited in 2014. The Institute for Scientific Information (ISI) announces IF values for the previous year each summer.
There are subtleties to the IF calculation, such as adjustments for citations by a journal of its own published articles. There are also variations to IF, such as the cited half-life and immediacy index to provide further insight into the impact of a journal. In some countries, IF is used to evaluate the performance of academic faculty.
The distribution of IF values is skewed. Some well-known journals have an IF several times higher than those of competitive journals. For example, the New England Journal of Medicine and Lancet greatly out-distance other general medical journals. A useful context to evaluate Pharmacotherapy’s IF is within the scientific category assigned by ISI. Pharmacotherapy ranks 104th out of 254 journals considered by ISI in the subject category Pharmacology and Pharmacy. In 2014, the IF for Pharmacotherapy (2.662) was higher than that of journals often publishing similar content, including the Journal of Clinical Pharmacology (2.475), Annals of Pharmacotherapy (2.059), and American Journal of Health-System Pharmacy (1.882).
The reviewers, editors, and board of directors who are responsible for the publication of Pharmacotherapy are dedicated to producing the highest-quality journal possible. The high IF of Pharmacotherapy has many benefits: authors have more readers download and cite their work, ACCP has greater visibility of official position statements and commentaries, and the field of pharmacotherapy benefits from greater dissemination of the journal’s articles.