Journal impact factor and its importance for AFP.

BACKGROUND: In 2008, Australian Family Physician (AFP) was accepted on the list of journals listed in Science Citation Index Expanded and, thus, will generate an impact factor over the next 2 years. Impact factor is important to authors from research and academic backgrounds and will make AFP an increasingly attractive journal in which to publish. AIM: To describe the impact factor, its method of calculation, and its flaws. DISCUSSION: Impact factor is the number of a journal's cited research papers divided by the total number of citable papers it has published. It is distorted by several different factors: sub-discipline, region, basic versus applied research, and whether the journal editor deliberately tries to strategically increase their impact factor. CONCLUSION: Impact factor is an oversimplified single measure of 'impact', which may underestimate the contribution of the AFP to society. However, no accepted alternative metric currently exists.