The distribution of online healthcare information: a case study on melanoma.

To understand the difficulties users face when retrieving comprehensive healthcare information, this paper analyzes how facts related to a widely available healthcare topic are distributed across high-quality webpages. An inter-rater experiment with two skin-cancer physicians helped identify 14 facts necessary for a comprehensive understanding of melanoma risk and prevention. A second inter-rater experiment analyzed how those facts were distributed across 189 relevant webpages from high-quality sites. The analysis revealed that the distribution of facts is highly skewed, where few pages have many facts, many pages have a few facts, and no single page or site provides all the facts. A more detailed analysis suggests that the distribution is being caused by a trade-off between depth and breadth, leading to the existence of general, specialized, and sparse pages. Furthermore, the analyses reveal patterns and complexities in the relationships between facts, pages, and websites. These distribution results pinpoint the difficulties faced by searchers, and provide insights for the design of future systems that guide users in retrieving comprehensive healthcare information.