## 1 Introduction and Backgrounds
### Earlier Works Related to FRAM and Decision Ladder
Several works that mentioned information requirements were highly related to the display or interface requirements of an information system [34]. An early study on information requirements elicitation as a part of interface design for complex production processes was proposed by [20]. Three cognitive systems engineering methods were compared to identify the information requirements, namely: Abstraction Hierarchy as a system-based analysis, Hierarchical Task Analysis, and Control Task Analysis using decision ladder, as two task-based analyses. This study showed that the information requirements extracted from the system- and task-based analyses were mutually reinforcing, leading to a more comprehensive set of information requirements. In our study, we also combined a system-based analysis and a task-based analysis. The decision ladder was included as the final step in [33]'s four-step hybrid Cognitive Task Analysis (hCTA) framework aiming to generate information and display requirements for futuristic systems. Similar to our approach, the identification of tasks (or functions) involved in the work domain preceded the decision ladder modeling. The hCTA framework has several continued studies, for example, [35] used hCTA to generate display information requirements. A decision ladder is applied to guide the semi-structured interviews and to generate the information requirements for human-machine interfaces of radiotherapy equipment in [34]. The approach to dividing the task phases was not specified, whereas, in our study, we applied FRAM to identify the functions/tasks. This study also considered the distribution of the information requirements through time and space by analyzing when, where, and how the information shall be required by whom using heuristic analysis. FRAM can be applied to perform similar analyses. **FRAM and the decision ladder combination. ** FRAM has been combined with various methods, as presented in a non-exhaustive survey by [36]. The decision ladder has also been combined with various approaches or integrated as a framework, such as the Cognitive Work Analysis (CWA) framework [2]. Unlike FRAM which can be applied independently, the decision ladder requires a preceding analysis to identify the tasks in the work domain. For example, in the CWA, the decision ladder is used to perform control task analysis, the second step after work domain analysis using the Abstraction Hierarchy. To the best of our knowledge, our study is the first attempt to combine FRAM and decision ladder to elicit requirements. In [37], the authors proposed a concept to combine FRAM with conceptual design and Cognitive Work Analysis (CWA) to specify information systems requirements. They described the roles of each approach, namely, contextual design as the process of information identification, CWA as the procedures of mental models identification, and FRAM as the method of functions modeling. The decision ladder was not mentioned explicitly, however, it is the default method for the second phase of CWA [2]. However, we could not find a continued study to verify the attempt to combine FRAM and the decision ladder. **FRAM and decision ladder trends. ** FRAM is a promising method to model a modern system that is complex, dynamic, and consists of technical-human-organizational interactions, the so-called complex socio-technical system. Lately, research about FRAM is growing in various directions; there are efforts to strengthen its scientific basis, such as the quantification of FRAM [38], to promote the practical use of FRAM, such as the integration of FRAM with HYSIS Dynamics simulators [39], and to expand the application domains of FRAM [13]. In the case of the decision ladder, despite being an early method, researchers still apply this method steadily for decision-making analysis, decision support system design, and as a new supporting tool to solve various problems.