Turkiye Klinikleri Journal of Biostatistics

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EWMA Kontrol Çizelgeleri ve Sağlık Alanında Kullanımına Genel Bir Bakış
EWMA Control Charts and an Overview of Usage in Health
İsmet DOĞANa, Nurhan DOĞANa
aBiyoistatistik ve Tıbbi Bilişim AD, Afyonkarahisar Sağlık Bilimleri Üniversitesi Tıp Fakültesi, Afyonkarahisar, TÜRKİYE
Turkiye Klinikleri J Biostat. 2019;11(1):72-82
doi: 10.5336/biostatic.2019-64924
Article Language: TR
Full Text
ÖZET
 Tıpta kalite kontrolü her geçen gün daha fazla ilgi görmektedir. Bir kontrol çizelgesi, istatistiksel olarak belirlenen limitlere göre ölçülen bir işlemin performansını grafiksel olarak temsil eden veri noktaları içerir. Kontrol çizelgelerinin amacı, bir sürecin kontrol altında olup olmadığını ve bu süreçteki varyasyonun ortak veya özel nedenlerden kaynaklanıp kaynaklanmadığını tespit etmektir. Kontrol çizelgesi, 1920'lerin başlarında Shewhart tarafından geliştirilen, en başarılı istatistiksel süreç kontrol aracıdır. Kontrol çizelgesinin kullanılmasının temel amacı, değişimi ve kaynağını inceleyerek zaman içinde süreç performansını izlemek, kontrol etmek ve iyileştirmektir. Literatürde çok sayıda farklı kontrol çizelgesi mevcuttur. EWMA ve CUSUM dışındaki grafikler, bir histogram üzerinde çizildiğinde simetrik ve çan şeklindeki normal dağılıma sahip veriler için en uygun olanlardır. EWMA ve CUSUM çizelgeleri ise Lognormal, Exponential, Binomial, Poisson ve Geometrik rasgele değişkenler de dahil olmak üzere diğer veri türleri için geliştirilmiştir. Bu yazının odak noktası EWMA çizelgesidir. Bu yazıda EWMA istatistiksel süreç kontrol metodolojisi ve tıp alanındaki uygulamaları gözden geçirilecektir. EWMA çizelgesi, verilerdeki küçük değişiklikleri belirleyebildiğinden ve çarpık veri dağılımları ile iyi performans gösterdiğinden seçilmiştir. EWMA çizelgesi, süreç parametrelerindeki küçük ve orta düzeydeki değişimleri saptamadaki mükemmel yeteneği nedeniyle şu anda yaygın bir şekilde kullanılmaktadır. Küçük değişiklikleri saptamak için çok esnek ve etkili bir çizelgedir ve normal dağılımın söz konusu olmadığı durumlarda sağlamlık gösterme avantajına sahiptir.

Anahtar Kelimeler: Kontrol çizelgesi; EWMA; istatistiksel süreç kontrolü
ABSTRACT
 Quality control in medicine is generating more and more interest everyday. A control chart contains data points that graphically represent the performance of a process, measured against statistically determined limits. The purpose of control charts is to ascertain whether a process is in control or out of control and, therefore, whether variation within that process is due to common or special causes. Control chart is the most successful statistical process control tool, originally developed by Shewhart in the early 1920s. The main purpose of using a control chart is to monitor, control, and improve process performance over time by studying variation and its source. There are a multitude of different types of control charts available in the literature. Charts, other than Exponentially Weighted Moving Average (EWMA) and CUSUM (Cumulative Sum) are most appropriate for normally distributed data, which are symmetric and bell shaped when plotted on a histogram. EWMA and CUSUM charts have been developed for other types of data as well, including Lognormal, Exponential, Binomial, Poisson, and Geometric random variables. The focus of this paper is the EWMA chart. In this paper, will review the methodology of EWMA statistical process control and its application in medical practice. The EWMA chart was selected since it is able to detect small shifts in the data and perform well with skewed data distributions. The EWMA chart has now been widely used because of its excellent ability to detect small to moderate shifts in the process parameters. It is a very flexible and effective chart for detecting small changes and has the advantage of showing robustness to non normality.

Keywords: Control chart; EWMA; statistical process control
REFERENCES:
  1. Mitra A. Control charts for the standard deviation. In: Ruggeri F, Kenett RS, Faltin FW, eds. Encyclopedia of Statistics in Quality and Reliability. 1st ed. England: John Wiley & Sons Ltd; 2007. p.1-12. [PubMed]
  2. Minne L, Eslami S, de Keizer N, de Jonge E, de Rooi SE, Abu-Hanna A. Statistical process control for validating a classification tree model for predicting mortality--a novel approach towards temporal validation. J Biomed Inform. 2012;45(1):37-44. [Crossref] [PubMed]
  3. Patil SH, Shirke DT. Economic design of a nonparametric EWMA control chart for location. Production. 2016;26(4):698-706. [Crossref]
  4. Lu SL. Tsai CF. Chen JH. EWMA control charts for statistical detecting QoS violations. 2015 IEEE 12th International Conference on e-Business Engineering; 2015.
  5. Hunter JS. The exponentially weighted moving average. J Qual Technol. 1986;18(4):203-10. [Crossref]
  6. Abreu RP, Schaffer JR. A double EWMA control chart for the individuals based on a linear prediction. J Mod Appl Stat Methods. 2017;16(2):443-57. [Crossref]
  7. Shah S, Shridhar P, Gohil D. Control chart: a statistical process control tool in pharmacy. Asian J Pharm. 2010;4(3):184-92. [Crossref]
  8. Swarbrick J. Encyclopedia of Pharmaceutical Technology. 3rd ed. Vol. 6. New York: Marcel Dekker Inc; 2007. p.3503.
  9. Abbas N. Homogeneously weighted moving average control chart with an application in substrate manufacturing process. Comput Ind Eng. 2018;120:460-70. [Crossref]
  10. Suman G, Prajapati DR. Control chart applications in healthcare: a literature review. Int J Metrol Qual Eng. 2018;9:5. [Crossref]
  11. Finison LJ, Finison KS, Bliersbach CM. The use of control charts to improve healthcare quality. J Healthc Qual. 1993;15(1):9-23. [Crossref] [PubMed]
  12. Benneyan JC, Lloyd RC, Plsek PE. Statistical process control as a tool for research and healthcare improvement. Qual Saf Health Care. 2003;12(6):458-64. [Crossref] [PubMed] [PMC]
  13. Moran JL, Solomon PJ. Statistical process control of mortality series in the Australian and New Zealand Intensive Care Society (ANZICS) adult patient database: implications of the data generating process. BMC Med Res Methodol. 2013;13:66. [Crossref] [PubMed] [PMC]
  14. Sasikumar R, Devi SB. Cumulative sum charts and its healthcare applications. Sri Lankan J Appl Stat. 2014;15(1):47-56. [Crossref]
  15. Baldewijns G, Luca S, Nagels W, Vanrumste B, Croonenborghs T. Automatic detection of health changes using statistical process control techniques on measured transfer times of elderly. Conf Proc IEEE Eng Med Biol Soc. 2015;2015:5046-9. [Crossref]
  16. Duclos A, Voirin N. The p-control chart: a tool for care improvement. Int J Qual Health Care. 2010;22(5):402-7. [Crossref] [PubMed]
  17. Neuburger J, Walker K, Sherlaw-Johnson C, van der Meulen J, Cromwell DA. Comparison of control charts for monitoring clinical performance using binary data. BMJ Qual Saf. 2017;26(11):919-28. [Crossref] [PubMed] [PMC]
  18. Human SW, Kritzinger P, Chakraborti S. Robustness of the EWMA control chart for individual observations. J Appl Stat. 2011;38(10):2071-87. [Crossref]
  19. Roberts SV. Control chart tests based on geometric moving averages. Technometrics. 1959;1(3):239-50. [Crossref]
  20. Borror CM, Champ CW, Rigdon SE. Poisson EWMA control charts. J Qual Technol. 1998;30(4):352-61. [Crossref]
  21. Carson PK, Yeh AB. Exponentially weighted moving average (EWMA) control charts for monitoring an analytical process. Ind Eng Chem Res. 2008;47(2):405-11. [Crossref]
  22. Noyez L. Control charts, Cusum techniques and funnel plots. A review of methods for monitoring performance in healthcare. Interact Cardiovasc Thorac Surg. 2009;9(3):494-9. [Crossref] [PubMed]
  23. Saeed N, Kamal S. The EWMA control chart based on robust scale estimators. Pakistan J Stat Oper Res. 2016;12(4):659-72. [Crossref]
  24. Areepong Y. Explicit formulas of average run length for a moving average control chart for monitoring the number of defective products. Int J Pure Appl Math. 2012;80(3):331-43.
  25. Azam M, Aslam M, Jun CH. An EWMA control chart for the exponential distribution using repetitive sampling. Oper Res Decisions. 2017;27(2):5-19.
  26. Reynolds Jr MR, Stoumbos ZG. Comparisons of some exponentially weighted moving average control charts for monitoring the process mean and variance. Technometrics. 2006;48(4):550-67. [Crossref]
  27. Patel AK, Divecha J. Modified exponentially weighted moving average (EWMA) control chart for an analytical process data. J Chem Eng Mater Sci. 2011;2(1):12-20.
  28. Haq A. A new nonparametric synthetic EWMA control chart for monitoring process mean. Commun Stat Simul Comput. 2018;1-12. [Crossref]
  29. Abbasi SA. A new nonparametric EWMA sign control chart. Expert Syst Appl. 2012;39:8503. [Crossref]
  30. Yang SF, Lin JS, Cheng SW. A new nonparametric EWMA sign control chart. Expert Syst Appl. 2011;38(5):6239-43. [Crossref]
  31. Waterhouse M, Smith I, Assareh H, Mengersen K. Implementation of multivariate control charts in a clinical setting. Int J Qual Health Care. 2010;22(5):408-414. [Crossref] [PubMed]
  32. Lowry CA, Woodall WH, Champ CW, Rigdon SE. A multivariate exponentially weighted moving average control chart. Technometrics. 1992;34(1):46-53. [Crossref]
  33. Zhang G, Chang SI. Multivariate EWMA control charts using individual observations for process mean and variance monitoring and diagnosis. Int J Prod Res. 2008;46(24):6855-81. [Crossref]
  34. Woodall WH, Adams BM, Benneyan JC. The use of control charts in healthcare. In: Faltin F, Kenett R, Ruggeri F, eds. Statistical Methods in Healthcare. 1st ed. New York: John Wiley & Sons Ltd; 2012. p.253-67. [Crossref]
  35. Braimah OJ, Osanaiye PA, Omaku PE, Saheed YK, Eshimokhai SA. On the use of exponentially weighted moving average (EWMA) control chart in monitoring road traffic crashes. Int J Math Stat Invention. 2014;2(5):1-9.
  36. Haq A. A new nonparametric EWMA control chart for monitoring process variability. Qual Reliab Eng Int. 2017;33(7):1499-512. [Crossref]
  37. Thaga K, Sivasamy R. Single variables control charts: a further overview. Indian J Sci Technol. 2015;8(6):518-28. [Crossref]
  38. Polunchenko AS, Sokolov G, Tartakovsky AG. Optimal design and analysis of the exponentially weighted moving average chart for exponential data. Sri Lankan J Appl Stat. 2014;15(2):55-82. [Crossref]
  39. Duttadeka S, Gogoi B. A study on exponentially weighted moving average control chart with parametric and nonparametric approach. J Agric Life Sci. 2014;1(2):1-16.

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