The Impact of Public Information on Pricing Dispersion and: Evidence from Housing Markets
Using data from Philadelphia housing transactions, this paper demonstrates that the availability of free online information, such as Zestimates and visual disclosures, significantly reduces pricing dispersion and improves market efficiency, particularly in heterogeneous housing markets where valuation uncertainty is highest.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
In the world of buying and selling, a gap often exists between what a seller asks for and what a buyer is willing to pay. This gap is not just a matter of negotiation; it is a sign of how much the two sides truly understand about the item's value. When buyers and sellers have different information, they hold different beliefs about what a house is worth, leading to a wider gap between the asking price and the final sale price. In financial markets, experts measure this uncertainty by looking at the difference between the price to buy and the price to sell an asset. In the world of real estate, where transactions are rare and every home is unique, researchers use a similar measure: the distance between the listed price and the actual price the home sells for. The bigger this distance, the more confusion and disagreement exist in the market. For decades, real estate agents held a significant advantage because they had access to private data and local knowledge that ordinary people did not. However, the rise of the internet has changed the landscape, offering free tools that allow anyone to see property values and detailed photos of homes. The question is whether this flood of free information has actually helped buyers and sellers agree on a price, or if the old advantages still hold sway.
A team of researchers set out to answer this question by examining the housing market in Philadelphia, Pennsylvania. They gathered data on 62,171 home transactions that took place between 2011 and 2018. Their goal was to see if two specific types of free online information—automated value estimates provided by the website Zillow and the number of photos available for a listing—made the gap between the asking price and the selling price smaller. They reasoned that if people had better access to facts about a home, they would be less confused, their beliefs about the value would align more closely, and the final deal would happen closer to the original asking price. To test this, they looked at different types of homes, from identical apartment units to unique, standalone houses, and watched how the price gap changed as online tools became more common over the years.
The researchers found that free online information did indeed shrink the gap between the asking price and the selling price, but the effect depended heavily on the type of house being sold. For homes that are very similar to one another, such as condominiums, the availability of an automated value estimate did not change the price gap at all. This makes sense because when every unit in a building is nearly identical, it is already easy to figure out what one is worth without needing a computer estimate. However, for homes that are more unique and varied, such as townhomes, semi-detached houses, and detached single-family homes, the results were different. For these more complex properties, where it is harder to guess the value because no two are exactly alike, the presence of a free online value estimate significantly reduced the price gap. The more photos available for these unique homes, the smaller the gap became as well. This suggests that when a house is hard to value, free digital tools act as a powerful equalizer, helping regular buyers and sellers get on the same page.
The study also revealed that the timing of when people started using these tools mattered. The researchers noticed that the positive effects of online information became much stronger after 2015. Before that year, fewer people were using these websites regularly, and the automated estimates were not as trusted or accurate. As the years passed and more households began to rely on these platforms, the impact on pricing grew. The data showed that for unique homes, the reduction in the price gap was most pronounced in the later years of the study, when the online tools had become a standard part of how people bought and sold houses. This indicates that the technology did not instantly fix the market; rather, its benefits grew as people learned to trust and use the information it provided.
One of the most striking findings was that this reduction in the price gap was not uniform across all sellers. The researchers observed that when a home was owned by a real estate agent or a member of their immediate family, the price gap was naturally smaller, even without the online tools. This confirms that agents already possess superior knowledge about the market. However, the introduction of free online information helped close the gap for everyone else, effectively reducing the advantage that agents held simply by having access to private data. In essence, the internet did not eliminate the need for agents, but it did level the playing field for the rest of the market. By providing clear, accessible facts about property values and conditions, these digital tools helped buyers and sellers negotiate with greater confidence, leading to deals that were closer to the true value of the home.
The researchers concluded that the impact of free information is not the same for every asset. It is most powerful in situations where uncertainty is highest. For standard, uniform products like condominiums, the market is already efficient, and extra information adds little value. But for unique, heterogeneous assets like detached houses, where valuation is difficult and opinions vary widely, free digital information acts as a crucial guide. It compresses the range of acceptable prices and helps the market function more smoothly. This suggests that in any market where people struggle to agree on value because the items are complex and varied, making high-quality information freely available can significantly improve how prices are discovered. The study offers a clear picture of how technology is reshaping the relationship between buyers, sellers, and the intermediaries who guide them, proving that when information flows freely, the fog of uncertainty begins to lift.
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