Decisions, decisions

One of the key drivers in the emergence of civil engineering systems in the 1960s as a field of discourse was the potential of developing greater engineering understanding using a range of systems models and the need for better engineering decisions and outcomes. Important engineering decisions generally fall into two types. Those that seek to minimise losses such as those associated with very low probability and high consequence catastrophic outcomes and those that seek to maximise opportunity between competing options. This short essay concerns the latter. The assessment of large-scale, wide impact engineering decisions has proved problematic. This stems from a number of factors. There are often many non-monetary impacts, the systems boundaries (in space and time) are not clear, the stakes are high and there are many stakeholders (some of whom are not involved in the decision process). All these factors mean that the use of Cost-Benefit analysis as a decision-making criterion is controversial, ambiguous and in some cases inappropriate. In addition, there are often other non-monetary factors to be considered. The consequence is that long-term infrastructure decisions get bogged down or deferred and the default decision is to do nothing.