Gdpnow is a prediction model (that has an alternate model that accounts for the gold move).
This is the actual calculation.
The uncorrected gdpnow number was too pessimistic while the human consensus was too optimistic. The corrected gdpnow number was pretty close (though last week nosedived too much). The early April gdpnow corrected number was bang on.
https://www.fisherinvestments.com/en-us/insights/market-comm...
Edit: here's a breakdown. It looks like imports (gold and tariff front running) were big negatives.
https://www.zerohedge.com/economics/us-q1-gdp-contracts-reco...