GDP Growth QoQ vs YoY: Why do the figures not match? According to statista.com, US Q4 GDP growth rate was 2.6% over the economy in Q3. However, why is the annualized growth rate for the US therefore not be a sum of all 4 quarters if their definition of QoQ growth is basically how much the economy grew over the previous quarter? i.e. why is according to statista, the GDP growth of the US in 2018-19 only 2.9%, and not 2.6 + 3.4 + 4.2 + 2.2?
Because those data are Seasonally adjusted annual rate: https://en.wikipedia.org/wiki/Seasonally_adjusted_annual_rate