Why two chart lines can both start at 100

Why two chart lines can both start at 100

FRED's Index transformation resets each selected series to 100 on a chosen date. If one line later reads 120 and another 110, that means gains of 20% and 10% relative to each line's own starting value. It does not say the first measure has a larger absolute level.

Rebasing helps compare growth paths across different units, but the chosen start date can change the visual story. Check the base date and original units before treating the gap between lines as an economic gap.