Impact Factor

For Reference Only


Definition

Impact factor (IF) is ideally a number that reflects the relative importance of an "average article" in a journal. ISI defined IF as the quotient of two numbers. The numerator is how often an article from a journal is cited, and the denominator is how many articles were published in that journal.

For example,
A = total cites in 2004
B = 2004 cites to articles published in 2002-2003 (this is a subset of A)
C = number of articles published in 2002-2003
Impact factor for 2004 = B/C

Some care has to be taken when interpreting these numbers. There are many factors that affect the citability of a paper, such the nature of the discipline, the breadth of the topic, citation habit of peer researchers in a field, etc. Comparison of journals in terms of impact factors should be made very carefully.

Furthermore, as impact factor has been taken by some universities and government funding agents as a measure of research quality, journal editors have taken strategies to improve impact factors of their journals in order to enhance journal reputations. Indeed, practical loopholes exist for jerking up of impact factors and hence it is important to realize the limited faithfulness of an impact factor as an objective indicator for reflecting a journal's true impact.

Impact factors statistics

Journal Names2005 IF2006 IF2008 IF2010 IF2011 IF2012 IF2013 IF2014 IF2015 IF
Automatica3.1782.1712.8292.9193.1323.023.635
Chaos1.7601.9262.1522.0812.0762.1881.7611.9542.049
Circuits, Systems and Signal Processing0.6460.1840.3960.7520.8170.9821.2641.1181.178
IET Circuits, Devices and Systems0.6380.4760.5150.5480.5471.0170.9120.5210.59
IET Communications0.3450.9630.8290.6370.720.7420.624
IET Computers and Digital Techniques0.3160.4840.4460.2840.360.3560.517
IET Electric Power Applications0.5870.2900.661.2121.1731.5621.3071.2111.358
IEEE Circuits & Systems Magazine1.1481.4391.6671.72.5173.000
IEEE J. Emerging and Selected Topics in Circuits and Systems1.5241.578
IEEE Trans. Aerospace & Electronic Systems0.7700.8361.0241.2301.0951.2991.3941.7571.672
IEEE Trans. Automatic Control3.2931.952.112.7183.1672.7792.777
IEEE Trans. Circuits & Systems I1.2521.1392.0431.4201.9702.242.32.4032.393
IEEE Trans. Circuits & Systems II0.6610.9221.4361.3201.4101.3271.1871.2341.136
IEEE Trans. Communications1.4901.2082.071.5121.6771.751.9791.9922.298
IEEE Trans. Computer-Aided Design of Integrated Circuits and Systems1.4661.2521.2711.0931.2031.0031.181
IEEE Trans. Electron Devices2.1052.0522.732.4452.3182.0622.3582.4722.207
IEEE Trans. Energy Conversion2.6192.262.2722.4273.3532.3262.596
IEEE Trans. Industrial Electronics0.5360.5905.4684.6785.1605.1656.56.4986.383
IEEE Trans. Industrial Informatics2.993.3818.785NA4.708
IEEE Trans. Information Theory2.1831.9383.7932.3573.0092.6212.652.3261.737
IEEE Trans. Power Electronics0.7541.0293.4832.9294.6504.085.7256.0084.953
IEEE Trans. Signal Processing 1.8201.5702.3352.2122.6282.8133.1982.7872.624
IEEE Trans. Wireless Communications3.181.7982.5753.742.5242.4962.925
IEEE Trans. Vehicular Technology0.8601.0711.3081.4881.9212.0622.6421.752.243
IEEE Sensors Journal1.521.4751.8521.7621.889
IEICE Trans. Electronics0.6080.4690.40.3330.3890.2810.344
IEICE Trans. Fundamentals of Electronics Communications and Computers0.3300.3120.4370.2260.2540.2380.2260.2310.236
Int. J. Bifurcation & Chaos0.8450.8660.870.8140.7550.9211.0171.0781.355
Int. J. Circuit Theory & Applications0.5770.6862.3892.0111.6251.2931.211.2541.179
J. Empirical Finance0.8070.9340.9370.7140.907
J. Statistical Mechanics: Theory and Experiment1.8221.7271.8662.0562.4042.091
Nature29.27326.68131.43436.10136.28038.59742.35141.45638.138
Physica A1.3321.3111.4411.5621.3731.6761.7221.7321.785
Physica D1.8631.6741.9264.9221.5941.6691.8291.6361.579
Physical Review E2.4182.4382.5082.42.2552.3132.3262.2882.252
Physical Review Letters7.4897.0727.187.3287.3707.9437.7287.5127.645
Physics Letters A1.5501.4682.1742.0091.6321.7661.6261.6831.677
Physics Letters B5.3015.0434.0345.0833.9554.5696.0196.1310.547
PLoS ONE4.34.4114.0923.733.5343.2343.057
Proceedings of the IEEE3.8873.6864.6134.8786.8106.9115.5464.9345.627
Proceedings of National Academy of Science USA9.389.7719.6819.7379.8099.7719.423
Quantitative Finance0.590.7350.8240.7540.6530.794
Science31.85330.02828.10329.74731.20131.02731.47733.61134.661

Source: ISI Web of Knoweledge, Journal Citation Report
CiteFactor


Last updated June 14, 2016; Michael Tse