title: Fitting power-laws in empirical data with estimators that work for all exponents.
abstract: Most standard methods based on maximum likelihood (ML) estimates of power-law exponents can only be reliably used to identify exponents smaller than minus one. The argument that power laws are otherwise not normalizable, depends on the underlying sample space the data is drawn from, and is true only for sample spaces that are unbounded from above. Power-laws obtained from bounded sample spaces (as is the case for practically all data related problems) are always free of such limitations and maximum likelihood estimates can be obtained for arbitrary powers without restrictions. Here we first derive the appropriate ML estimator for arbitrary exponents of power-law distributions on bounded discrete sample spaces. We then show that an almost identical estimator also works perfectly for continuous data. We implemented this ML estimator and discuss its performance with previous attempts. We present a general recipe of how to use these estimators and present the associated computer codes.
authors.affiliation: Section for Science of Complex Systems, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hanel
authors.affiliation: Section for Science of Complex Systems, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.
authors.forename: Bernat
authors.initials: B
authors.lastname: Corominas-Murtra
authors.affiliation: Section for Science of Complex Systems, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Section for Science of Complex Systems, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.|Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, United States of America.|IIASA, Schlossplatz 1, 2361 Laxenburg, Austria.|Complexity Science Hub Vienna, Josefstädterstrasse 39, A-1090 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Thurner
mesh_terms: D000465:Algorithms; D001499:Bayes Theorem; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D003657:Decision Making; D016013:Likelihood Functions; D008962:Models, Theoretical; D011336:Probability