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.