Impact factors and their significance; overrated or misused?

The journal impact factor (IF) is in widespread use for the evaluation of research and researchers, and considerable controversy surrounds it. The concept behind the IF is citations, and the number of them. The IF is a useful tool for the evaluation of journals, but it must be used carefully. Considerations include the number of review papers, letters or other types of material published in a journal, variations between disciplines, and item-by-item impact. Perhaps the most important use of the IF is in the process of academic evaluation. The extent to which the IF is appropriate for the evaluation of the quality of a specific article or journal and particularly for the evaluation of individual and collective research achievements is highly debatable.