SÃ¡ndor KemÃ©ny* is an emeritus professor at Budapest University of Technology and Economics, Faculty of Chemical Technology and Biotechnology, Department of Chemical and Environmental Process Engineering.

Sándor Kemény

, in which the authors discussed the identification of out-of-trend (OOT) data in the stability studies of single batches using a regression control chart method (1). 

	If several batches are considered, there are two different time scales. The first one is the life within batches, which has been covered in Part I (1). The regression control chart uses this within-batch context. The second time scale is the order of batches. Two approaches are followed in this Part II article. The by-time-point method uses the between-batches context only, while the multivariate approach uses both between-batches and within-batches contexts.


	Submitted: April 5, 2017
	Accepted: June 27, 2017

	Máté Mihalovits is a PhD student, mihalovits@mail.bme.hu; and Sándor Kemény* is an emeritus professor, Tel.: +36 309936307, kemeny@mail.bme.hu, both at Budapest University of Technology and Economics, Faculty of Chemical Technology and Biotechnology, Department of Chemical and Environmental Process Engineering Hungary, 1111. Budapest, MÅ±egyetem rakpart 3.

	* To whom all correspondence should be addressed.


	Vol. 41, No. 12
	December 2017
	Pages: 38–43, 45

	When referring to this article, please cite it as M. Mihalovits and S. Kemény, "Methods for Identifying Out-of-Trend Data in Analysis of Stability Measurements–Part II: By-Time-Point and Multivariate Control Chart," 

Articles

In Part I of this article series, the authors discussed the regression control chart method for identifying out-of-trend data in pharmaceutical stability studies. In Part II, the by-time-point method and the multivariate control chart method are investigated, and improved approaches are suggested. The method is illustrated using real data sets.

Methods for Identifying Out-of-Trend Data in Analysis of Stability Measurements—Part II: By-Time-Point and Multivariate Control Chart

	The regulation of pharmaceutical stability studies still lacks universally accepted techniques regarding the identification of out-of-trend data. Three methods have been suggested for identifying out-of-trend data in pharmaceutical stability studies: the regression control chart, the by-time-point method, and the slope control chart. In Part I of this article series, the regression control chart method is investigated, and an improved approach is suggested. The method is illustrated using realistic data. In Part II, the by-time-point method and the multivariate control chart method will be discussed.


	Submitted: March 22, 2017
	Accepted: June 27, 2017


	Vol. 41, No. 11
	November 2017
	Pages: 46–53

	When referring to this article, please cite it as M. Mihalovits and S. Kemény, "Methods for Identifying Out-of-Trend Data in Analysis of Stability Measurements–Part I: Regression Control Chart," 

In Part I of this article series, the regression control chart method for identifying out-of-trend data in pharmaceutical stability studies is investigated, and an improved approach is suggested. 