Information visualisation to support informed decision-making under uncertainty and risk

Informed decision-making (IDM) depends on the availability of adequate information and the ability of decision-makers to manipulate this information. More often than not, the information on which decisions are based is subject to variability and uncertainty arising from different sources. Consequently, risk accompanies decisions as there is a chance that the decision taken can lead to an undesirable rather than a desirable outcome. Ignoring uncertainty and its associated risk may simplify the decision-making process, but it does not lead to making informed decisions. Thus, they should be explicitly considered from the beginning of the decision-making process as an integral part of the information on which decisions are based. Information visualisation (InfoVis) can play an important part in assisting people to make informed decisions under uncertainty and risk. It provides an effective means for depicting information in ways that make it amenable to analysis and exploration. It also can facilitate the integration of uncertainty into the decision-making process and raise the awareness of decision-makers about its effects. This thesis presents the design and evaluation of a new InfoVis tool to support informed decision-making under uncertainty and risk. First, the information requirements and main considerations underpinning the design and evaluation of the InfoVis tool presented in this thesis have been identified. Second, an InfoVis tool for portraying information about the decision problem and raising the awareness of decision-makers about the uncertainty and risk associate with decision-making, called VisIDM, has been designed and implemented. VisIDM consists of two main parts: Decision Bars and Risk Explorer. Decision Bars provide overview information of the decision problem under uncertainty and risk through three panels: the Outcome, Risk, and Likelihood Bars. Risk Explorer provides decision-makers with a multivariate representation of uncertainty and risk associated with the decision alternatives. It facilitates the interactive analysis and comparison of available alternatives, either consecutively or simultaneously, at different levels of detail. Third, the usefulness of VisIDM for assisting people to make informed decisions has been evaluated through a qualitative user study. The study has also investigated how VisIDM was used by participants and what features support their exploration and perception of information. The results of the study suggest that VisIDM is a useful tool for assisting people to make informed decision under uncertainty and risk. It provides them with a variety of information and assists them in performing several operations to arrive at their final decisions. It also raises people’s awareness of the uncertainty and risk associated with decision-making and facilitates their analysis and exploration at different levels of detail. The results also show that although different types of information that people may need to make their decisions are presented in VisIDM, they tend to rely on a single or small number of salient pieces of information rather than on a systematic consideration and evaluation of all available information. In addition, people have problems in understanding and interpreting the uncertainty and risk information. In particular, they have a tendency to ignore the importance of probability information and rely, in large part, on the consequences of undesirable outcomes to form their impression about the risk. Moreover, the availability of information may not contribute greatly to people’s feeling of increased confidence that they can make informed decisions. Rather, their ability to manipulate and comprehend information would enhance their confidence to make informed decisions