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

Published on: 
Pharmaceutical Technology, Pharmaceutical Technology-12-02-2017, Volume 41, Issue 12
Pages: 38–43, 45

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.


This article is a continuation of Part I, 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.


Peer-Review Article
Submitted: April 5, 2017
Accepted: June 27, 2017

About the Authors

Máté Mihalovits is a PhD student,; and Sándor Kemény* is an emeritus professor, Tel.: +36 309936307,, both at Budapest University of Technology and Economics, Faculty of Chemical Technology and Biotechnology, Department of Chemical and Environmental Process Engineering Hungary, 1111. Budapest, Műegyetem rakpart 3.

* To whom all correspondence should be addressed.

Article Details

Pharmaceutical Technology
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," Pharmaceutical Technology 41 (12) 2017.