What is Money Illusion?
Money illusion, a concept introduced by economist Irving Fisher in 1928, describes the tendency to think about money in nominal terms rather than real purchasing power. When inflation runs at 3% and you receive a 2% raise, you are nominally richer but actually poorer in real terms. Most people perceive this as a gain because the number on their paycheck increased, even though their purchasing power declined by 1%.
Impact on Investment Decisions
Money illusion causes investors to overvalue nominal returns. A savings account paying 0.5% feels safe, but with 3% inflation, it loses 2.5% in purchasing power annually. Real estate buyers celebrate that their home doubled in value over 25 years without recognizing that cumulative inflation may account for most of that increase. Evaluating all returns in nominal terms systematically overstates investment performance and understates the erosion of cash holdings.
Overcoming Money Illusion
Train yourself to think in real terms by always subtracting inflation from any return figure. A 7% portfolio return during 3% inflation is really 4%. Set retirement goals in today's purchasing power, then inflate them to future nominal values. If you need $40,000 per year in today's dollars and plan to retire in 30 years with 2.5% average inflation, you will need approximately $84,000 in nominal terms to maintain the same lifestyle.