Fig 3. Possible scenarios explaining a changing Impact Factor (IF).

(A) Based on theoretical considerations regarding the potential influence of the variables (citations and article numbers) on the final calculation (i.e. the IF quotient), 13 scenarios are possible which either cause an increased (a1-a5), constant (b1-b3) or decreased IF (c1-c3). In those scenarios where necessary, the size of the arrows indicate the relative importance of the changes (articles (Δ(art)) versus citations (Δ(cit))). (B) The validity of these IF changes as a parameter of (changing) journal quality is categorized and referred to as either ‘valid’ (highlighted green) or ‘invalid’ (highlighted red). See text for further explanation.