1.Statistical and methodological considerations for reporting RCTs in medical literature.
Korean Journal of Anesthesiology 2015;68(2):106-115
Randomized controlled trials (RCTs) are known to provide the most reliable evidence on intervention. However, RCTs are often conducted and reported incompletely and inadequately, making readers and reviewers unable to judge the validity and reliability of the trials. In this article, we consider the statistical and methodological issues involved in reporting on RCTs, particularly in relation to the objectives, designs, and commencements of trials. This paper deals with the various issues that should be considered in presenting RCTs, and suggests checklists for reporting on them. We expect that these checklists will remind readers and reviewers to evaluate manuscripts systematically and comprehensively, making those manuscripts more transparent and reliable.
Checklist
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Methods
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Reproducibility of Results
2.Statistical data presentation.
Korean Journal of Anesthesiology 2017;70(3):267-276
Data are usually collected in a raw format and thus the inherent information is difficult to understand. Therefore, raw data need to be summarized, processed, and analyzed. However, no matter how well manipulated, the information derived from the raw data should be presented in an effective format, otherwise, it would be a great loss for both authors and readers. In this article, the techniques of data and information presentation in textual, tabular, and graphical forms are introduced. Text is the principal method for explaining findings, outlining trends, and providing contextual information. A table is best suited for representing individual information and represents both quantitative and qualitative information. A graph is a very effective visual tool as it displays data at a glance, facilitates comparison, and can reveal trends and relationships within the data such as changes over time, frequency distribution, and correlation or relative share of a whole. Text, tables, and graphs for data and information presentation are very powerful communication tools. They can make an article easy to understand, attract and sustain the interest of readers, and efficiently present large amounts of complex information. Moreover, as journal editors and reviewers glance at these presentations before reading the whole article, their importance cannot be ignored.
Methods
5.Should we prove the balance of baseline data in randomized controlled trials?
Korean Journal of Anesthesiology 2019;72(2):89-90
No abstract available.
7.Standard deviation and standard error of the mean.
Dong Kyu LEE ; Junyong IN ; Sangseok LEE
Korean Journal of Anesthesiology 2015;68(3):220-223
In most clinical and experimental studies, the standard deviation (SD) and the estimated standard error of the mean (SEM) are used to present the characteristics of sample data and to explain statistical analysis results. However, some authors occasionally muddle the distinctive usage between the SD and SEM in medical literature. Because the process of calculating the SD and SEM includes different statistical inferences, each of them has its own meaning. SD is the dispersion of data in a normal distribution. In other words, SD indicates how accurately the mean represents sample data. However the meaning of SEM includes statistical inference based on the sampling distribution. SEM is the SD of the theoretical distribution of the sample means (the sampling distribution). While either SD or SEM can be applied to describe data and statistical results, one should be aware of reasonable methods with which to use SD and SEM. We aim to elucidate the distinctions between SD and SEM and to provide proper usage guidelines for both, which summarize data and describe statistical results.
10.What is the proper way to apply the multiple comparison test?.
Korean Journal of Anesthesiology 2018;71(5):353-360
Multiple comparisons tests (MCTs) are performed several times on the mean of experimental conditions. When the null hypothesis is rejected in a validation, MCTs are performed when certain experimental conditions have a statistically significant mean difference or there is a specific aspect between the group means. A problem occurs if the error rate increases while multiple hypothesis tests are performed simultaneously. Consequently, in an MCT, it is necessary to control the error rate to an appropriate level. In this paper, we discuss how to test multiple hypotheses simultaneously while limiting type I error rate, which is caused by α inflation. To choose the appropriate test, we must maintain the balance between statistical power and type I error rate. If the test is too conservative, a type I error is not likely to occur. However, concurrently, the test may have insufficient power resulted in increased probability of type II error occurrence. Most researchers may hope to find the best way of adjusting the type I error rate to discriminate the real differences between observed data without wasting too much statistical power. It is expected that this paper will help researchers understand the differences between MCTs and apply them appropriately.
Analysis of Variance
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Hope
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Inflation, Economic