Chapter 7 presents discussion of the results obtained in the panel study, the aim of which was to examine the influence of intra-individual variability on the average semester growth rates (ASGRs) of syntactic complexity, lexical complexity, accuracy, and fluency (CALF) in L2 English writing at secondary school. The results of the panel study align with previous research findings in CDST. Firstly, the study showed that the development of complexity, accuracy, and fluency in L2 writing is a complex, dynamic, and non-linear process. Secondly, it demonstrated that the CALF variables enter different types of competitive, supportive, pre-conditional, and dual relationships, and that more competition takes place between complexity, accuracy, and fluency, while more support occurs within syntactic and lexical complexity. Thirdly, the study provided evidence for intermittent periods of stability and variability in the development of CALF variables and detected some qualitative peaks and phase transitions. The study also revealed that complexity, accuracy, and fluency develop at different rates per semester and over the whole educational level. Although former studies have found that intra-individual variability is related to progress and proficiency gains, this study has shown that it influences the rate of growth. Nevertheless, the study has some limitations with regard to the research design, data analysis, and research validity.