User reviews are an essential source of information for consumers, exerting a considerable influence on purchase decisions. In general, reviews rated as more helpful exert a greater influence downstream. But how do the linguistic characteristics of a review affect its helpfulness? Thanks to HKUST’s Sang Kyu Park and two colleagues, marketers now have fresh insights into how the linguistic objectivity or subjectivity of a review affects its value to consumers.

“Considering that objective information is often seen as more useful, because it generalizes beyond idiosyncrasies,” the researchers note, “one might intuit that objectivity should increase review helpfulness while subjectivity should decrease it.” The question remains, however, whether this intuition holds empirically and across all types of consumer goods.

To help answer this question, the researchers used a convolutional neural network (CNN) to analyze the linguistic subjectivity and objectivity of over 2 million reviews on Amazon. “We define subjectivity as aspects of language used to express opinions or personal evaluations and objectivity as those used to convey facts,” they explain.

While subjective and objective sentences each had a positive main effect on review helpfulness, subjectivity had a stronger positive effect than objectivity, especially in hedonic domains—products and services that consumers purchase primarily for enjoyment rather than utilitarian purposes, such as jewelry and DVDs.

Intriguingly, the authors also found that the interactive effect of subjectivity and objectivity was negative. “The majority of users might inadvertently undermine the impact of their reviews by combining objective and subjective perspectives,” they warn. It may be useful for marketers to encourage customers to focus on subjective experiences when reviewing hedonic products and objective benefits when reviewing utilitarian goods.

“Beyond online reviews,” the researchers conclude, “our findings suggest that communications might be more persuasive if they focused on either subjective or objective arguments, rather than using them both.”