Debt Snowball vs. Avalanche: Debt Account Aversion and the Kellogg Study

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The debt snowball lists debts from smallest balance to largest, ignoring interest rates, pays the minimum on all of them, and sends every extra dollar to the smallest until it is gone, then rolls that payment into the next. The episode walks through an example: credit cards of $250 and $500, a $2,500 car loan and a $5,000 personal loan, with $100 a month freed up. The first card is gone in two months, the second three months later, the car six months after that, and the loan six months later, debt free in 17 months. It notes that installment lenders may need explicit instructions to apply extra payments to principal.

The rival debt avalanche, ordered by interest rate, wins on math, and even Dave Ramsey concedes that while arguing personal finance is 20 percent head knowledge and 80 percent behavior. Research explains the pull of quick wins: a 2012 Kellogg School of Management study at Northwestern, a 2016 Harvard Business Review analysis, and debt account aversion research by Moty Amar and colleagues. Other work complicates the picture, including Federal Reserve survey data in which a slight majority reported the avalanche worked better and a 2023 paper framing the snowball through nudge theory.

• Paying in reverse order, the $250 card would have taken 10 months of minimum payments to clear at the end.
• The sources stress that neither method works unless the imbalance between income and spending is fixed first.
• The 2012 Kellogg study found people who tackle small balances first are more likely to eliminate their overall debt.
• The 2016 Harvard Business Review work found the portion of a balance eliminated, not the dollar amount, most drives a sense of progress.
• In Amar's simulations, debtors shown the exact interest cost of their choices tended to make the mathematically optimal decision.