ASSESSING QUALITY IN HIGH-UNCERTAINTY MARKETS: ONLINE REVIEWS OF CREDENCE SERVICES

In economics of information theory, credence products are those whose quality is difficult or impossible for consumers to assess, even after they have consumed the product (Darby & Karni, 1973). This dissertation is focused on the content, consumer perception, and power of online reviews for credence services. Economics of information theory has long assumed, without empirical confirmation, that consumers will discount the credibility of claims about credence quality attributes. The same theories predict that because credence services are by definition obscure to the consumer, reviews of credence services are incapable of signaling quality. Our research aims to question these assumptions. In the first essay we examine how the content and structure of online reviews of credence services systematically differ from the content and structure of reviews of experience services and how consumers judge these differences. We have found that online reviews of credence services have either less important or less credible content than reviews of experience services and that consumers do discount the credibility of credence claims. However, while consumers rationally discount the credibility of simple credence claims in a review, more complex argument structure and the inclusion of evidence attenuate this effect. In the second essay we ask, “Can online reviews predict the worst doctors?” We examine the power of online reviews to detect low quality, as measured by state medical board sanctions. We find that online reviews are somewhat predictive of a doctor’s suitability to practice medicine; however, not all the data are useful. Numerical or star ratings provide the strongest quality signal; user-submitted text provides some signal but is subsumed almost completely by ratings. Of the ratings variables in our dataset, we find that punctuality, rather than knowledge, is the strongest predictor of medical board sanctions. These results challenge the definition of credence products, which is a long-standing construct in economics of information theory. Our results also have implications for online review users, review platforms, and for the use of predictive modeling in the context of information systems research.

On Experiencers and Minimality

This dissertation is concerned with experiencer arguments, and what they tell us about the grammar. There are two main types of experiencers I discuss: experiencers of psychological verbs and experiencers of raising constructions. I question the notion of ‘experiencers’ itself; and explore some possible accounts for the ‘psych-effects’. I argue that the ‘experiencer theta role’ is conceptually unnecessary and unsustained by syntactic evidence. ‘Experiencers’ can be reduced to different types of arguments. Taking Brazilian Portuguese as my main case study, I claim that languages may grammaticalize psychological predicates and their arguments in different ways. These verb classes exist in languages independently, and the psych-verbs behavior can be explained by the argument structure of the verbal class they belong to. I further discuss experiencers in raising structures, and the defective intervention effects triggered by different types of experiencers (e.g., DPs, PPs, clitics, traces) in a variety of languages. I show that defective intervention is mostly predictable across languages, and there’s not much variation regarding its effects. Moreover, I argue that defective intervention can be captured by a notion of minimality that requires interveners to be syntactic objects and not syntactic occurrences (a chain, and not a copy/trace). The main observation is that once a chain is no longer in the c-command domain of a probe, defective intervention is obviated, i.e., it doesn’t apply. I propose a revised version of the Minimal Link Condition (1995), in which only syntactic objects may intervene in syntactic relations, and not copies. This view of minimality can explain the core cases of defective intervention crosslinguistically.