It's about time: How to study intertemporal choice in systems design

Context: Decision making pervades software and systems engineering. Intertemporal decisions involve trade-offs among outcomes at different points in time. They play a central role in systems design, as recognised since the inception of the software engineering (SE) field. They are also crucial for the sustainability of design decisions. However, temporal decision making is not adequately understood in SE. The field of Judgement and Decision Making (JDM) offers important empirical findings and research methods that could be utilised.Objective: This article establishes a baseline for studying how software professionals handle intertemporal choices. It examines how temporal distance affects choices in an example scenario, explores in what areas of software development such decisions can be found, and examines how systems design decisions can be characterised and studied as intertemporal.Method: We developed a method to study intertemporal choice in SE, based on an initial set of psychological theory grounded in JDM. We instantiated the method in a study to elicit responses to an intertemporal choice task followed by a Cognitive Task Analysis (CTA) interview.Results: We found that study participants overall tended to discount future outcomes, but individual partici-pants varied wildly in how they valued present vs. future outcomes. They indicated several locations in which intertemporal choices occur in everyday software development. Based on these findings, and by reconciling our initial theory with existing JDM theory and results, we further developed and refined our theory and study method into a framework for studying intertemporal decision making in SE.Conclusions: To obtain a basis for more sustainable software systems design decisions, SE research should adopt a more comprehensive, detailed, and empirically consistent way of understanding and studying intertemporal choices. We provide suggestions for how future research could achieve practical methods that address essential characteristics of real-life systems design decisions.