Economists, investors, financial journalists, and politicians should stop comparing today's interest rate expenses with those of 30 years ago.

A lot has changed. - Debt-to-GDP has risen from less than 70% to more than 110%. An increase of more than 60%. - Potential GDP growth has declined from roughly 3% to roughly 2%. - The ratio of people over 65 to the working-age population has more than doubled. - Social security spending has increased by more than 5% of GDP. Yet we keep hearing: interes — via @jsblokland

Debt-to-GDP surge from under 70% to over 110% invalidates 30-year rate comparisons.