The new administration (Trump’s second term) began on January 20, 2025, so the first 100 days ran to about April 30, 2025.(en.wikipedia.org)

By that 100‑day mark, GDP data clearly reflected the impact of tariffs and spending cuts:

• Q1 2025 real GDP, covering January–March and released April 30, showed a –0.3% annualized contraction, the first since 2022. Multiple analyses attributed this to a record import surge as firms front‑loaded purchases ahead of Trump’s broad April tariff package, plus a sharp drop in federal spending.(cnbc.com)
• Detailed breakdowns noted imports up over 40% and federal government spending down about 5.1%, explicitly linking the decline to aggressive budget cuts and layoffs.(indilegalonline.com) A business‑economics review summed it up by saying Q1 GDP “highlight[ed] tariff impacts,” underscoring how the data revealed the directional effect of the new trade policy.(cbia.com)

Employment data in the same window captured the effects of federal cuts and policy uncertainty:

• February and March jobs reports showed moderating payroll growth (roughly 150k–220k per month) and unemployment edging around 4.1–4.2%, with commentary that mass federal layoffs from the new Department of Government Efficiency and tariff uncertainty were key headwinds, even as private‑sector hiring continued.(theguardian.com) This made the early labor‑market effects of the administration’s fiscal and trade stance visible.

Inflation data plus forward‑looking forecasts tied tariffs to the future price path:

• CPI reports for February and March 2025 showed inflation temporarily cooling (headline around 2.4–2.8% year‑over‑year), but economists repeatedly stressed that the announced April tariff package was not yet in the data and was expected to push prices higher later in 2025.(reuters.com) Major forecasters (e.g., Goldman Sachs) raised their projections for 2025 core PCE inflation to about 3.5% specifically because of the tariff program.(investopedia.com)

Markets and forecasters used these first‑100‑day data to reset expectations about growth, jobs, and inflation:

• As tariffs and spending cuts were rolled out and Q1 data arrived, Goldman Sachs and others repeatedly cut 2025 growth forecasts and lifted recession probabilities (to ~35–65%), explicitly citing the combined drag from higher tariffs, tighter fiscal policy, and weaker confidence.(fortune.com) A June 2025 NABE survey likewise showed consensus GDP forecasts marked down versus pre‑April and identified tariff impacts as the dominant downside risk to growth and employment.(nabe.com) Analysts also parsed Q1 GDP into “core” domestic demand versus tariff‑driven trade distortions to better project the path of real activity.(cbia.com)

Putting this together: within roughly the first 100 days, the observed trajectories of GDP (headline contraction with tariff‑driven trade distortion and reduced government spending), employment (slower gains with visible federal layoffs), and inflation (temporarily subdued but forecast to rise on tariffs) were already being used by economists and markets to model the directional impact of the administration’s spending cuts and tariff policy. That matches Friedberg’s claim that the first 100 days would be “pretty telling” for understanding those effects and for improving forward forecasts, so the prediction is best judged as right.