Compare indicators
Each line rebased to 100 where the shared window begins — growth from a common base, not levels.
Each series rebased to 100 at Jan 1960. birth_rate, fed_funds_rate · read from cache, latest-revised.
- Birth Rate
Births per 1,000 people in a year.
Crude birth rate: live births per 1,000 people in a year (World Bank/CDC via FRED).
- Federal Funds Rate
The interest rate the Fed sets to steer the economy.
Effective federal funds rate, monthly average.
Each measured on its own terms — compare the lenses, not just the lines. Full lessons → Learn
…and that proves nothing. Two lines moving together is not one moving the other. Almost any pair of trending economic series correlates highly — they share the same long climb of growth, prices, and population, or it is chance. r measures co-movement over this exact window, never cause. Change the range or swap a series and watch r move. Why correlation isn’t causation →