Why We Ignore Supposedly Irrelevant Factors—and What It Costs Us

Traditional economics predicts that irrelevant details—like how results are presented or your mood at decision time—don’t matter. But a parade of experiments and real-world stories says otherwise. For instance, in an economics classroom, students complained bitterly about a midterm with a low average score, despite the grading curve being identical to prior tests. In the next exam, only the raw point total changed—not the grading or difficulty. Students felt happier and performed just as well. The only difference was how numbers looked on paper.

Behavioral scientists call these elements SIFs—'supposedly irrelevant factors.' They infiltrate decisions everywhere. Psychologists Amos Tversky and Daniel Kahneman cataloged hundreds of predictable patterns where the context or presentation—framing, anchoring, even the labeling of cash discounts versus surcharges—bends choices. Tiny nudges in context can inspire buyers, unsettle employees, or tip policy outcomes.

Ignoring SIFs leads to poor predictions and missed opportunities, but spotting them allows us to design better experiences and more accurate forecasts. Over time, accepting the power of SIFs leads to honest, practical economics—and smarter strategies in work and life.

Throughout the week, pick five decisions you make and jot down any odd factor influencing you, whether it's what you ate, where you were, or how information was presented. Ask yourself if traditional logic would claim it’s irrelevant, and note the real impact. By naming these seemingly small but powerful details, you'll start to see how they drive outcomes, not just in your life but everywhere. Talk about them with friends and be ready to revisit your assumptions—because what looks irrelevant at first is often the drive behind the scenes.