In 2014, I started working on the PhD project, which aims at understanding the causes and consequences of university graduates following different types of career pathways. On route to achieving this aim, I faced a challenging task of deriving a typology, which was theoretically meaningful and suitable for further quantitative analysis. As the standard approach for deriving typologies using sequence analysis proved to be ineffective in this context, I decided upon a theoretically driven approach. Based on the theoretical literature surrounding the research topic, I derived a set of criteria for mutually exclusive types. On the basis of these criteria, I allocated each graduate's career into a type. Although the theoretically driven approach is not the most effective in all scenarios, in this case, it allowed me to achieve the purpose of this task. This research case provides an account of this aspect of my PhD project, taking the reader through the context of the challenge I faced when deriving this typology, a brief history of the use of sequence analysis in the social sciences, a step-by-step description of how the method was typically used in the previous studies, and some challenges related to the application of this method to socioeconomic trajectories. I then illustrate how I adapted the method on an example of economic activity histories of the university graduates who participated in the 1970 British Cohort Study, and conclude with some practical lessons I learned from this process, which are also applicable to other quantitative analyses. [This content is provided in the format of an e-book.]