Research Article To Compare Time-Weighted Graphs to Evaluate the Inclination of the Acetabular Component of Patients Who Had Total Hip Replacement Surgery Leman Tomak, 1 Yuksel Bek, 1 and YJlmaz Tomak 2 1 Department of Biostatistics and Medical Informatics, Faculty of Medicine, Ondokuz Mayis University, 55139 Samsun, Turkey 2 Department of Orthopedics and Traumatology, Faculty of Medicine, Ondokuz Mayis University, 55139 Samsun, Turkey Correspondence should be addressed to Leman Tomak; lemantomak55@gmail.com Received 4 November 2014; Accepted 20 January 2015 Academic Editor: Juan A. Sanchis-Gimeno Copyright © 2015 Leman Tomak et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Time-weighted graphs are used to detect small shifs in statistical process control. Te aim of this study is to evaluate the inclination of the acetabular component with CUmulative SUM (CUSUM) chart, Moving Average (MA) chart, and Exponentially Weighted Moving Average (EWMA) chart. Te data were obtained directly from thirty patients who had undergone total hip replacement surgery at Ondokuz Mayis University, Faculty of Medicine. Te inclination of the acetabular component of these people, afer total hip replacement, was evaluated. CUSUM chart, Moving Average chart, and Exponentially Weighted Moving Average were used to evaluate the quality control process of acetabular component inclination. MINITAB Statistical Sofware 15.0 was used to generate these control charts. Te assessment done with time-weighted charts revealed that the acetabular inclination angles were settled within control limits and the process was under control. It was determined that the change within the control limits had a random pattern. As a result of this study it has been obtained that time-weighted quality control charts which are used mostly in the feld of industry can also be used in the feld of medicine. It has provided us with a faster visual decision. 1. Introduction Statistical process control (SPC) methods, utilizing the increasingly available routinely collected electronic patient records, could be used in continuous monitoring of clinical outcomes using routinely collected data [1, 2]. Te “control charts” are a sequential analysis statistical tool that is partic- ularly suited to the identifcation of small changes or changes in the number of cases, in one direction or another [1–3]. Control chart is an efective tool to identify specifc causes of extreme variability. To distinguish the causes of variability, one of the most important visible signs is extreme observation on the control chart [1–3]. If some observations are outside the control limits, it means that the process is an out-of- control process, and the balance of the process is deteriorated. So corrective operations are needed so that the process can be controlled [2, 4]. If the process is in-control, the test results of patients are reported, but if it is out-control, the process is rejected and the results of tests are not reported [5]. Te diferent control charts can be used for the evaluation process. While some of them are suitable for attribute data such as p-chart, np-chart, c-chart, and u-chart; some are used for continuous data such as individual, moving range, X-bar, range, standard deviation. Tere are also other control charts which are used for various purposes apart from these. Te most important of them are time-weighted control charts. Tey are preferred in some situations where Shewhart charts did not detect the case of small shifs. Tere are CUmulative SUM chart, Moving Average chart, and Exponentially Weighted Moving Average (Geometric Moving Average) chart in this group [1, 4, 6, 7]. In the last decade, there has been a growing interest in the application of these techniques to the medical practice, especially evaluating and ofen promoting the use of con- trol charts assessment of performance in three main areas: trainees’ acquisition of competence in procedural skills [8, 9]; Hindawi Publishing Corporation BioMed Research International Volume 2015, Article ID 129610, 6 pages http://dx.doi.org/10.1155/2015/129610