To shoppers, a long line at the cash register or a messy sweater display is the price of procrastinating. To a savvy industry insider, these things have deeper meaning: Which store is taking market share? Have payroll reductions left staffing too thin?

Dozens of Wall Street analysts who cover the apparel sector scour malls regularly—picking through markdown racks, dining at food courts—in the search for clues about which merchandise bets have paid off and which have flopped.

Wall Street Analyst Hits the Stores

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Bryan Derballa for The Wall Street Journal

John Morris scans shopping bags to gauge where shoppers are making purchases.

Amid the final holiday crush at Westfield Garden State Plaza, a massive shopping center on 136 acres in Paramus, N.J., there were many signals of how the holidays season is going.

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