Many of us believe trust is an increasingly important research topic in HCI. It is believed that trust can increase the efficiency of collaboration. It is important to understand how trust is produced and perceived in computer-mediated environments in order to better design the platforms that facilitate collaboration. To do any of these, we need to have a measure of trust in order to understand the effects of different factors and designs on trust. How to construct this measure of trust, however, is not always obvious. This post sets out to distinguish two ways of measuring trust, tied to two distinct views of trust in the past literature.
According to my literature review (80+ papers and books), there are two views of trust: the over-socialized, and the under-socialized. Trust touches every aspect of people’s lives, therefore, trust can either be viewed as a macro, structural phenomenon, or a micro individual process with very specific targets (A trusts B to do X).
The over-socialized view of trust originates from Luhmann in the late 1970s, who describes trust as “a mechanism for the reduction of social complexity” . This follows the social systems tradition of that of Parsons. Trust in this context is usually discussed very theoretically and philosophically, making it difficult to generate empirical evidence, especially before large scale data collection became a reality. Trust in this context is usually measured by the trust question in General Social Survey (GSS) or the World Values Survey (WVS), “Generally speaking, would you say that most people can be trusted or that you can’t be too careful in dealing with people?” Whenever we read articles with titles like The Decline of Trust in the United States, chances are they are using data from GSS. This measure and its variations have been widely used particularly in political science. For example, questions like “How much of the time do you think you can trust the government in Washington to do what is right?” by Miller . However, these measures have also been criticized for so many reasons (I don’t want to elaborate), particularly for having little predictive power when it comes to specific behaviors of individuals.
This brings to other extreme, the under-socialized view of trust, focusing on micro, individual decisions and traits, and primarily held by economists and psychologists. The strength of this view is its ability to gather empirical evidence through experiments with small groups of participants. For example, the “trust game” by Berger  is an investment game that uses the amount of investment to denote the level of trust in the participant’s partner. The psychologists Rotter developed the Rotter Interpersonal Trust Scale (ITS) consisting 25 items, asking whether experts, parents, students, repairmen, salesmen and organizations could be trusted . The outcome of this measure is considered as an individual trait similar to personality trait. But if you read the items closely, some items are actually quite broad and bearing a lot of similarity with the GSS, such as “Most people can be counted on to do what they say they will do.” It is unclear how much ITS can predict specific behavior. For example, perhaps item 23 on the scale, “Most repairmen will not overcharge, even if they think you are ignorant of their specialty”, can predict the adoption of TaskRabbit, but it is hard for me to imagine if item 24, “A large share of accident claims filed against insurance companies are phony” is equally predictive.
To summarize, there are many different ways to measure trust, such as general attitude question, investment game, scale with specifically designed items. With our increasing ability to collect data, such as outcome (e.g. whether a crowdfunding project is funded or not), maybe we can develop new ways of measuring trust that is not possible before, and bridge the gap between individual level behavior and view, with the macro system dynamics.
Feel free to comment if you have a specific question related to how to measure trust and I’ll try my best to reply.
 Niklas Luhmann. Trust and Power, Two works by Niklas Luhmann, 1979.
 Arthur H Miller. Political issues and trust in government: 1964–1970. American Political Science Review, 68(03):951–972, 1974.
 Joyce Berg, John Dickhaut, and Kevin McCabe. Trust, reciprocity, and social history. Games and economic behavior, 10(1):122–142, 1995.
 Julian B Rotter. A new scale for the measurement of interpersonal trust1. Journal of personality, 35(4):651–665, 1967.