Reliability trust & Decision trust

Although it is easy to recognize Trust and it’s manifestations in everyday life, it is challenging to define trust. For example the definition by Kuntze et al (2008) “trust means an entity always behaves in the expected manner for the intended purpose” this definition would seem to the reader as a good holistic definition, but the definition assumes that all entities behave, which is not true, as we have non-behavioral entity such as data. Another example, the definition by Jøsang (1997) he says trust means an entity “will resist attacks from malicious agents”, this definition covers only one side of the trust issue, as it is also important to trust entity even though it is known there will be no attacks from malicious agents, which was neglected in this definition.

In 2007 Jøsang recognized that trust could be seen as two types: “reliability trust” and “decision trust”.  Reliability trust can be seen as trustworthiness of someone or something, for example in a medical procedure how reliable is the surgeon (resource) who is doing this procedure (is he trustworthy). Or how reliable is this procedure (process), how many times was it success (is it trustworthy process). Gabetta in (1990) defined trust in a way that can formulate ‘reliability trust’, he says: “Trust is the subjective probability by which an individual, A, expects that another individual, B, performs a given action on which A’s welfare depends”.

However trust is not only about ‘reliability trust’, as Falcone & Castelfranchi (2001) noted that even having a high reliability trust is not enough to depend on this resource, or this process. They suggested introducing some saturation-based method to influence the decision trust. They define ‘decision trust’ as: “Trust is the extent to which a given party is willing to depend on something or somebody in a given situation with a feeling of relative security, even though negative consequences are possible” (Falcone & Castelfranchi, 2001). To illustrate the difference between the two types of trust lets go back to the previous medical procedure example. If a Hart Rate Monitor device known to be ‘not reliable’ (40% of the time gives faulty results), in a normal scheduled surgery, the surgeon will avoid depending on such device (resource) and would ask to replace it, but if there was an emergency situation that require an immediate surgery and this device was the only one available, the surgeon will likely use and depend on this devise even though it is known to be unreliable. So even though the reliability trust in the resource is same on both situations, decision trust was different within the same process. That shows even though trustworthiness (reliability trust) is a very important factor, but it is not the only factor affecting decision trust, and there are other factors such as situation context, associated risk, environmental factors, and possible outcomes, which might affect the decision trust. Reliability trust could be represented in a discrete degree of reliability (i.e. in percentage “%”), where decision trust is mostly represented in a binary decision (i.e. trust, or do not trust) (for more on trust and how we reach this definition please refer to the literature review).

So what is Trust in terms of BPM. As it is obvious from the definition, to solve the problem of ‘Trust’, we need to solve the problem of ‘Decision trust’, which mainly depends on ‘Reliability trust’, plus other factors that might affect the decision. So, to solve the problem of trust in BPM, first we need to define ‘Reliability trust’ (or trustworthiness) and how it would be solved in BPM, and then we need to analyze what other factors that might affect ‘Decision trust’ beside the trustworthiness, and how to asses them and include them in a mathematical way to be able to calculate the ‘Decision trust’ automatically.