IJAHP Essay: Kahraman/A brief literature review for fuzzy AHP International Journal of the Analytic Hierarchy Process 293 Vol. 10 Issue 2 2018 ISSN 1936-6744 https://doi.org/10.13033/ijahp.v10i2.599 A BRIEF LITERATURE REVIEW FOR FUZZY AHP Cengiz Kahraman Department of Industrial Engineering Istanbul Technical University 34367 Besiktas, Istanbul, Turkey AHP is an effective tool for dealing with complex hierarchical decision making problems. It divides a large complex problem into small and easily solvable sub- problems and then combines the solutions of these small problems in order to obtain the solution of the larger problem. Consistency measurement of the pairwise comparison matrices is another useful component of AHP. It uses a 1 to 9 scale whose linguistic expressions are defined accordingly. However, the representation of a linguistic term by an exact number may not fully reflect a decision maker’s judgments in his/her mind. Fuzzy numbers and scales have been developed to consider this issue in the literature. After ordinary fuzzy sets have been extended to new fuzzy types of sets such as type-2 fuzzy sets, intuitionistic fuzzy sets, hesitant fuzzy sets, Pythagorean fuzzy sets, and neutrosophic sets, new extensions of fuzzy AHP have been proposed by various authors accordingly. A brief literature review on fuzzy AHP studies is given. The Scopus database was utilized for this literature review. When the term “Fuzzy AHP” was searched in article title, abstract, and keywords, 2,066 documents were found. Figure 1 illustrates the number of documents by their publication years. After 2003, the number of documents on fuzzy AHP sharply increases. Figure 2 presents the countries publishing fuzzy AHP papers and the numbers of publications. China, Iran, Turkey, India, and Taiwan are the five leading countries in this area. Figure 3 shows the types of documents written about fuzzy AHP. Articles on fuzzy AHP and conference papers are by far the leading types of documents written about fuzzy AHP. Figure 4 presents the classification of fuzzy AHP documents by their subject areas. Engineering and computing sciences are the leading subject areas followed by business, management and account, mathematics, and decision sciences. In the special topic articles section, three papers on the theoretical development and/or practical usage of fuzzy AHP are presented. I hope these papers will provide a useful resource of ideas, techniques, and methods for research on fuzzy AHP. IJAHP Essay: Kahraman/A brief literature review for fuzzy AHP International Journal of the Analytic Hierarchy Process 294 Vol. 10 Issue 2 2018 ISSN 1936-6744 https://doi.org/10.13033/ijahp.v10i2.599 Figure 1 Number of publications on fuzzy AHP by their year Figure 2 Countries publishing fuzzy AHP papers 0 50 100 150 200 250 1988 1993 1998 2003 2008 2013 2018 Publication on fuzzy AHP by years 0 100 200 300 400 500 600 700 C h in a Ir a n T u rk e y In d ia T a iw a n U n it e d S ta te s M a la y si a U n it e d K in g d o m S o u th K o re a C a n a d a In d o n e si a H o n g K o n g It a ly Ja p a n A u st ra li a F ra n c e S e rb ia M o ro c c o T h a il a n d L it h u a n ia S p a in G e rm a n y D e n m a rk G re e c e P o la n d V ie t N a m B a n g la d e sh Q a ta r S a u d i A ra b ia B ra z il P h il ip p in e s S in g a p o re N e th e rl a n d s U n it e d A ra b E m ir a te s B e lg iu m C o lo m b ia C z e c h R e p u b li c N ig e ri a S o u th A fr ic a T u n is ia Number of documents by their countries IJAHP Essay: Kahraman/A brief literature review for fuzzy AHP International Journal of the Analytic Hierarchy Process 295 Vol. 10 Issue 2 2018 ISSN 1936-6744 https://doi.org/10.13033/ijahp.v10i2.599 Figure 3 Types of documents on fuzzy AHP 0 200 400 600 800 1000 1200 1400 Article Conference Paper Book Chapter Review Conference Review Article in Press Erratum Book Note Types of documents on fuzzy AHP IJAHP Essay: Kahraman/A brief literature review for fuzzy AHP International Journal of the Analytic Hierarchy Process 296 Vol. 10 Issue 2 2018 ISSN 1936-6744 https://doi.org/10.13033/ijahp.v10i2.599 Figure 4 Classification of fuzzy AHP documents by their subject areas 0 200 400 600 800 1000 1200 Classification of fuzzy AHP documents by their subject areas IJAHP Essay: Kahraman/A brief literature review for fuzzy AHP International Journal of the Analytic Hierarchy Process 297 Vol. 10 Issue 2 2018 ISSN 1936-6744 https://doi.org/10.13033/ijahp.v10i2.599 REFERENCES Atanassov, K.T. 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