ORIGINAL PAPER Proposed the ANOVA Method for Analysis of Proﬁciency Test Result R. Hegazy*, M. I. Mohamed and A. Abu-Sinna National Institute of Standards (NIS), El-Haram, Egypt Received: 14 August 2014 / Accepted: 06 December 2015 Ó Metrology Society of India 2016 Abstract: Analysis of variance ‘‘ANOVA’’, as a trustful statistical method most commonly applied to the results of the experiment to determine the percent contribution of each factor, is used in this paper in comparison with Z-score statistical method. Z-score, Zeta score, and En number are the most credible statistical methods used in proﬁciency testing evaluation. In this paper four different PT examples were demonstrated, both ANOVA as well as Z-score were used for the analysis of the testing. The ﬁrst example showed a consistency of the results between both of them, however in the other three examples dissimilarity happened between the two results. While Z-score gave the participant laboratory a satisfactory result, ANOVA gave the same laboratory unsatisfactory result. Final results showed the advantage and reliability of ANOVA analysis over Z-score analysis. Keywords: Proﬁciency test; ANOVA; Z-score 1. Introduction The proﬁciency test (PT) is a powerful tool to help a laboratory to demonstrate its competence [1]. Proﬁciency testing deter- mines the performance of individual laboratories for speciﬁc tests or measurements and is used to monitor laboratories’ continuing performance. Proﬁciency testing is also called interlaboratory comparison. As this term implies, proﬁciency testing compares the measuring results obtained by different laboratories. In a proﬁciency test one or more artifacts are sent around between a numbers of participating laboratories. Each laboratory measures the artifacts according to a given set of instructions and reports its results to the administrator. The results reported by each laboratory for a measurand are compared to the reference value for that measurand [2]. The reference value can be determined in various ways. The two most common ways are to use a reference laboratory or use the average of the values reported by the participants. The following are some of the potential beneﬁts which may be available to participating laboratories [3, 4]: • Conﬁrming competent performance • Identifying testing or measurement problems • Comparing methods and procedures • Improving performance • Educating staff • Instilling conﬁdence in staff, management and external users of laboratory services • Comparing operator capabilities • Generating reference materials • Determining method precision and accuracy • Satisfying regulators and accreditation bodies • Providing laboratories with additional risk management. Appropriate statistical design of a proﬁciency testing scheme is essential. Data analysis method should be chosen in such a way to truly describe the variation of the results between the participating laboratories [5]. The aim of this research is to give a new statistical methodology for comparing the proﬁciency testing results. The present work is proposed using the ANOVA analysis, through using the F distribution to compare the results of the proﬁciency tests. Some different examples on hardness test are analyzed by Z score and ANOVA. Following are a presentation for some of the most credible statistical methods used in proﬁciency testing evaluation. 2. Methodology In proﬁciency testing, usually output data is treated using different analysis criteria, mostly are; Z-score, Zeta-score, *Corresponding author, E-mail: rihamhegazy@yahoo.com M  APAN-Journal of Metrology Society of India DOI 10.1007/s12647-015-0163-z 123