China's gross domestic expenditure on research and development reached roughly $668 billion in 2021 on a purchasing-power-parity basis, overtaking the United States' $607 billion, OECD Main Science and Technology Indicators (MSTI) data show. The shift, first confirmed in the OECD's 2023 release and examined in The Conversation, moves China from second to first in aggregate R&D outlays — a reordering with implications that reach well beyond citation counts and league tables.

What does the headline number actually measure?

The roughly $61 billion PPP gap inflates when converted at market exchange rates. At 2021 dollar rates, US R&D spending reached about $580 billion against an estimated $451 billion in China. PPP conversion lifts China's figure close to 50% because labour and capital costs measure higher in parity terms. PPP remains the OECD's default for cross-country comparison; market-rate figures matter more for procurement teams calculating actual contract dollars.

How different is the spending mix?

The aggregate figure conceals structural divergences. China's GERD-to-GDP ratio stood at 2.55% in 2022, against an estimated 3.45% for the US. China leads on volume; the US still leads on intensity.

The functional split is where the gap widens:

• Basic research: about 6.5% of Chinese GERD versus roughly 15% of US GERD in 2022
• Applied research: roughly 11% in both systems
• Experimental development: about 77% of Chinese outlays versus 70% in the US

For R&D managers planning product-scale prototyping, the Chinese share signals a partner base with deep engineering bench strength. For principal investigators hunting blue-sky collaborators, US universities still offer a denser basic-research ecosystem.

Who pays the bill?

Business enterprises finance roughly 77% of Chinese GERD and 75% of US GERD, OECD data show.

The gap surfaces in government shares. Chinese central and provincial governments fund about 19% of national R&D; the US federal government supplies around 11%, with state, university and non-profit sources covering the remainder.

State-owned enterprises and central-government laboratories in China concentrate strategic spend on semiconductors, quantum information, biotechnology and clean-energy hardware — sectors tightening under US and EU export controls.

Where does the comparison break down?

OECD notes definitional alignment has improved since 2007 but flags residual gaps in software, military R&D and in-house enterprise R&D. China's National Bureau of Statistics revised its methodology in 2021, raising historical GERD by roughly 10%. NSF's Business R&D and Innovation Survey (BRDIS) remains a US-specific benchmark without a direct Chinese parallel.

What should procurement and partnership teams do with it?

• Re-benchmark partner scoring on functional mix, not headline totals. Chinese prototyping depth and US basic-research density send different buy signals.
• Treat PPP conversions as policy indicators and market-rate figures as procurement reality.
• Track export-control lists and subsidy disclosures quarterly — strategic funding in both jurisdictions is shifting faster than the headline aggregate.

What does the trajectory look like?

The Conversation frames China's overtaking as a rebalancing rather than displacement. Aggregate R&D totals are projected to diverge further by 2027, with the US retaining advantages in basic-research share, university-led spinouts and consortium financing. For portfolio managers, the question is less whether China leads on volume, and more which jurisdiction absorbs which stage of the pipeline.