Comparison Tables Are Decision Machines: Design Them to Deliver a Verdict

Jakob Nielsen argues that comparison tables exist to help people decide, and that AI assistants now build their own, so tables need specific, sourced values in place of checkmarks.

Comparison tables set products side by side so that shoppers can judge them without holding every detail in memory. Jakob Nielsen, a usability researcher who writes on his site UX Tigers, gives 48 guidelines for designing them. He warns that many tables made by sellers work as advertising, and that AI assistants now build comparison tables of their own from whatever data they find.

• When a seller's column is a solid row of checkmarks and rivals lose on hand-picked rows, shoppers who spot one rigged row distrust the whole table.
• Nielsen advises citing the source and date of every contested claim. Each cell should make sense alone, such as "Battery life: 17 hours (video playback)" in place of "17".
• A shopper who already has an AI-built table often visits the product page only to confirm one value. Nielsen calls this short visit a "checkthrough".
• He also advises sellers to publish honest comparisons with their main rivals, including the rows where they lose.

A product team now writes comparison data for two readers: an AI assistant that copies the values, and a person who checks one of them. Nielsen argues that specific values with a source serve both.

Derived by Working Surface from the article. Source line: AI agents now assemble comparison tables of their own from whatever data they can find, and a wall of checkmarks gives them precious little to work with.

19 September 2026: AI makes prototypes, apps and comparisons cheap, and their worth depends on what is settled first or can be checked.