The impact of visual formats on product rating interpretation

In today’s digital-first economy, ratings have become one of the most influential factors in consumer decision-making. From choosing a hotel on Agoda to buying electronics on Shopee or Tiki, consumers routinely rely on numerical feedback from previous customers. But new research reveals a hidden cognitive bias: people interpret the same rating differently depending on how it is visually represented.

A recent study from the Cornell SC Johnson College of Business, published in the Journal of Marketing Research, found that fractional star ratings tend to be overestimated, while equivalent numerical ratings are often underestimated. This insight is especially relevant for online retailers and platforms in Vietnam, where e-commerce is growing rapidly and product ratings are central to customer trust.

In a series of six experiments, researchers demonstrated that visual representation – whether using stars or Arabic numerals – can significantly alter how consumers perceive product quality. According to Deepak Sirwani, lead author and assistant professor at the University of British Columbia, the brain completes the image of fractional stars, such as 3.5 stars, giving a mental impression closer to 4 stars. In contrast, the same 3.5 displayed as a number is processed more analytically, causing consumers to anchor on the lower digit, "3," and thus perceive the rating more negatively.

The science behind perception gaps in ratings

The researchers conducted a foundational experiment involving 616 participants who were shown product ratings from 1.0 to 5.0 in 0.25-point increments, either as stars, numbers, or both. Participants were asked to visually place each rating on an unmarked scale. The results were consistent: star-based ratings were judged as higher than their numerical equivalents, especially when the score involved fractions like 3.5 or 4.25.

The underlying psychology, according to co-author Manoj Thomas, professor at Cornell, lies in how the brain processes different types of visual information. “The brain representations that are activated when you process stars are completely different from those activated by Arabic numerals,” he said. “That realization was the a-ha! moment.”

This perceptual bias means that fractional star ratings may unintentionally inflate consumer expectations, leading businesses to overpromise and underdeliver, which can negatively impact long-term brand trust. On the other hand, using numeric formats may make a product appear less favorable than it actually is, potentially reducing sales.

The team’s research also references earlier findings suggesting that even small changes in perceived rating can significantly affect purchasing behavior. While the exact sales impact varies by context, their experiments consistently showed that display format alone can shape consumer impressions.

Implications for Vietnam’s e-commerce and review culture

Vietnam’s e-commerce sector continues to expand rapidly, with platforms such as Shopee, Tiki, and Lazada integrating rating systems as central parts of their interfaces.

On these platforms, product ratings are displayed in both numeric and star formats - sometimes simultaneously - affecting user impressions during quick browsing. This research suggests that emphasizing fractional stars may create more favorable perceptions compared to plain numbers, especially in visually-driven interfaces like mobile apps.

Moreover, platforms experimenting with visual-driven commerce - such as TikTok Shop - may further benefit from optimized rating displays. As Vietnamese consumers increasingly shop through livestreams and social channels, the presentation of product quality cues will become even more impactful.

Although Vietnam-specific data on rating perception is limited, global trends still offer applicable insights for local businesses. For instance, a Nielsen study reported that 40% of online shoppers globally wouldn’t purchase electronics without reading online reviews first - a trend likely mirrored in Vietnam’s tech-savvy urban markets.

Toward more transparent and consistent rating standards

While the use of stars may benefit product appeal, the researchers advise caution. Visual cues that unintentionally mislead can damage consumer trust if expectations are not met. “Ratings have become as powerful a predictor of purchase as price, brand, or even recommendations from friends and family,” said Sirwani.

Their findings highlight a growing need for standardization and transparency in digital rating systems. For developers and platform managers in Vietnam, this could mean reviewing how fractional scores are rendered across mobile, desktop, and social channels to ensure consistency and avoid unintended misperceptions.

The format in which product ratings are displayed—stars or numbers—can significantly shape consumer perception. For businesses in Vietnam’s rapidly evolving online marketplace, understanding and ethically managing these subtle visual effects presents an opportunity to build stronger trust and increase conversion. Adopting more transparent and psychologically informed design standards may be the next step in elevating Vietnam’s digital retail experience.

Journal Reference: Deepak Sirwani, Srishti Kumar, Manoj Thomas. Overestimating Stars, Underestimating Numbers: The Hidden Impact of Rating Formats. Journal of Marketing Research, 2025; DOI: 10.1177/00222437251322425