Statistical tools to aid in the assessment of critical process parameters

Assessing impact based solely on statistical significance (p-value) is not appropriate, because statistical significance does not take into account the strength of the relationship relative to the relevant quality requirements and can lead to the inclusion of relatively unimportant process parameters as critical elements of the control strategy. The International Conference on Harmonization (ICH) Q8(R2) (1) provides the following definitions: * CQA is defined as a physical, chemical, biological. or microbiological property or characteristic that should be within an appropriate limit, range, or distribution to ensure the desired product quality. * CPP is a process parameter whose variability has an impact on a critical quality attribute and therefore should be monitored or controlled to ensure the process produces the desired quality.