# ALGORITHM 643: FEXACT: a FORTRAN subroutine for Fisher's exact test on unordered r×c contingency tables

@article{Mehta1986ALGORITHM6F, title={ALGORITHM 643: FEXACT: a FORTRAN subroutine for Fisher's exact test on unordered r×c contingency tables}, author={Cyrus R. Mehta and Nitin R. Patel}, journal={ACM Trans. Math. Softw.}, year={1986}, volume={12}, pages={154-161} }

The computer code for Mehta and Patel's (1983) network algorithm for Fisher's exact test on unordered r×c contingency tables is provided. The code is written in double precision FORTRAN 77. This code provides the fastest currently available method for executing Fisher's exact test, and is shown to be orders of magnitude superior to any other available algorithm. Many important details of data structures and implementation that have contributed crucially to the success of the network algorithm…

## 193 Citations

### A remark on algorithm 643: FEXACT: an algorithm for performing Fisher's exact test in r x c contingency tables

- Computer ScienceTOMS
- 1993

The network algorithm of Mehta and Patel [1986] is currently the best general algorithm for computing exact probabilities in r × c contingency tables with fixed marginals. Given here are some…

### An efficient algorithm for the exact test on unordered 2 X J contingency tables with equal column sums

- Mathematics
- 1997

### A comparison of algorithms for exact analysis of unordered 2 × K contingency tables

- Computer Science
- 1996

### A major improvement to the Network Algorithm for Fisher's Exact Test in 2×c

- Computer ScienceComput. Stat. Data Anal.
- 2006

### Exact Inference for Kendall's S and Spearman's ρ with Extension to Fisher's Exact Test in r × c Contingency Tables

- Mathematics
- 1994

Abstract We formulate the problem of exact inference for Kendall's S and Spearman's D algebraically, using a general recursion formula developed by Smid for the score S with ties in both rankings.…

### Extreme probabilities for contingency tables under row and column independence with application to fisher's exact test

- Mathematics
- 1988

Theorerms are proved for the maxima and minima of IIRi!/IICj!/T!IIyij ! over r× c contingcncy tables Y=(yij) with row sums R1,…,Rr, column sums C1,…,Cc, and grand total T. These results are…

### A Survey of Exact Inference for Contingency Tables

- Mathematics
- 1992

The past decade has seen substantial research on exact infer- ence for contingency tables, both in terms of developing new analyses and developing efficient algorithms for computations. Coupled with…

### Efficient Exact p-Value Computation for Small Sample, Sparse, and Surprising Categorical Data

- Computer ScienceJ. Comput. Biol.
- 2004

A generic branch-and-bound approach to efficient exact p-value computation is defined and the required conditions for successful application are enumerated, which constitutes a first practical exact improvement over the exhaustive enumeration performed by existing statistical software.

### A comparative study on approximative and exact tests in two-dimensional contingency tables

- Mathematics
- 2007

Often the statistician is faced with the necessity of analysing a × b-contingency tables which are partially very sparsely occupied beyond a very-well occupied “kernel”. The weak part shall not be…

### Fisher Exact Scanning for Dependency

- Computer Science, MathematicsJournal of the American Statistical Association
- 2018

It is shown that there exists a coarse-to-fine, sequential generative representation for the MHG model in the form of a Bayesian network, which implies the mutual independence among the Fisher’s exact tests completed under FES.

## References

SHOWING 1-10 OF 15 REFERENCES

### Computing an Exact Confidence Interval for the Common Odds Ratio in Several 2×2 Contingency Tables

- Computer Science, Mathematics
- 1985

Abstract A quadratic time network algorithm is provided for computing an exact confidence interval for the common odds ratio in several 2×2 independent contingency tables. The algorithm is shown to…

### A Network Algorithm for Performing Fisher's Exact Test in r × c Contingency Tables

- Mathematics
- 1983

A novel technique that considerably extends the bounds of computational feasibility of the exact test is proposed here and is transformed into one of identifying all paths through a directed acyclic network that equal or exceed a fixed length.

### A network algorithm for the exact treatment of the 2×k contingency table

- Mathematics
- 1980

A common statistical problem encountered in biomedical research is to test the hypothesis that the parameters of k binomial populations are all equal. An exact test of significance of this hypothesis…

### A survey of algorithms for exact distributions of test statistics in r × c contingency tables with fixed margins

- Mathematics
- 1985

### An Algorithm for Finding the Exact Significance Levels of r × c Contingency Tables

- Computer Science
- 1981

An algorithm for calculating the exact permutation significance value for r × c contingency tables does not require the total enumeration of all tables consistent with the given marginals and is faster than existing algorithms.

### Counting the Number of r×c Contingency Tables with Fixed Margins

- Mathematics
- 1977

Abstract Exact and approximate methods are given for counting the number of r × c contingency tables with fixed margins. The approximate methods are extended to estimate the number of r × c × s…

### The art of computer programming: sorting and searching (volume 3)

- Physics
- 1973

Apparatus for supporting different nets for various sporting purposes including interengaging tubular rods which are arranged to interconnect and have ground engaging portions suitable to be useful…

### The Art of Computer Programming

- Engineering, Physics
- 1968

The arrangement of this invention provides a strong vibration free hold-down mechanism while avoiding a large pressure drop to the flow of coolant fluid.

### Exact significance testing to establish treatment equivalence with ordered categorical data.

- MathematicsBiometrics
- 1984

An efficient numerical algorithm for computing the exact significance level and a simple method for obtaining the asymptotic significance level are provided for establishing the therapeutic equivalence of two treatments that are being compared on the basis of ordered categorical data.

### Nonparametric Estimation for a Scale-Change with Censored Observations

- Mathematics
- 1983

Abstract Nonparametric point and interval estimators of the ratio of two scale parameters are given for arbitrarily right-censored data based on the idea of Hodges and Lehmann (1963). These…