Korean J Anesthesiol.  2017 Aug;70(4):407-411. 10.4097/kjae.2017.70.4.407.

Statistical data preparation: management of missing values and outliers

• Kwak SK
• Kim JH

• KMID: 2386293
• DOI: http://doi.org/10.4097/kjae.2017.70.4.407

Abstract

Missing values and outliers are frequently encountered while collecting data. The presence of missing values reduces the data available to be analyzed, compromising the statistical power of the study, and eventually the reliability of its results. In addition, it causes a significant bias in the results and degrades the efficiency of the data. Outliers significantly affect the process of estimating statistics (e.g., the average and standard deviation of a sample), resulting in overestimated or underestimated values. Therefore, the results of data analysis are considerably dependent on the ways in which the missing values and outliers are processed. In this regard, this review discusses the types of missing values, ways of identifying outliers, and dealing with the two.

Keyword

Bias; Data collection; Data interpretation; Statistics

MeSH Terms

Bias (Epidemiology)
Data Collection
Statistics as Topic