大学排名核心评价指标中博士学位授予数的意义解读

Among the four most widely referenced global university ranking systems — QS World University Rankings, Times Higher Education (THE) World University Rankings, U.S. News & World Report Best Global Universities, and the Academic Ranking of World Universities (ARWU) — the number of doctoral degrees awarded per institution consistently appears as a weighted indicator. In ARWU, for instance, the “Number of PhDs Awarded” contributes 20% to the overall score, a weight higher than that assigned to per-capita academic performance (10%) or the number of alumni winning Nobel Prizes (10%) [Shanghai Ranking Consultancy, 2024, ARWU Methodology]. Across all four systems, the proportion of faculty with terminal degrees and the institutional doctoral output together account for between 5% and 20% of the composite score, depending on the ranking body. According to the OECD’s 2023 Education at a Glance report, the United States alone conferred 56,740 research doctorates in 2021, while China awarded 72,145 — the two nations together producing roughly 48% of the world’s total doctoral graduates [OECD, 2023, Education at a Glance]. These figures underscore why a university’s doctoral production capacity is treated as a proxy for research intensity, faculty quality, and institutional maturity. This article unpacks the rationale behind that weighting, explains how each ranking system operationalises the metric, and discusses what prospective students and their families should infer — and what they should not — from a university’s doctorate count.

The Rationale: Why Doctoral Output Signals Research Capacity

The doctoral degree represents the highest level of academic training, requiring original research that advances a field. Universities that produce large numbers of PhDs are typically those with robust graduate programmes, well-funded laboratories, and active faculty who can supervise dissertations. In ranking methodology, the metric serves as a proxy for research infrastructure and institutional scale.

Data from the U.S. National Science Foundation (NSF) show that the 50 U.S. universities with the highest PhD production also account for 62% of all federally funded academic research expenditures [NSF, 2023, Survey of Earned Doctorates]. This correlation is not coincidental: doctoral students often serve as teaching assistants and research assistants, directly supporting faculty output. A high doctorate count therefore indicates a self-sustaining research ecosystem. For international applicants, a university with strong doctoral output is more likely to offer funded PhD positions, access to cutting-edge equipment, and a critical mass of peer researchers in specialised fields.

How Each Ranking System Weighs the Metric

QS World University Rankings: Faculty with PhDs

QS uses the proportion of academic staff holding a doctoral degree as one of its indicators, weighting it at 5% of the total score. The rationale is straightforward: a faculty body where nearly all members hold terminal degrees is assumed to deliver higher-quality teaching and research. In the 2025 QS rankings, institutions such as the California Institute of Technology and the University of Cambridge report 100% of academic staff with PhDs. However, this metric can disadvantage universities in countries where professional degrees (e.g., clinical medicine or law) are the norm for senior faculty, even when those faculty produce high-impact research.

Times Higher Education: Doctoral-to-Bachelor’s Ratio

THE incorporates a “Doctorate-to-Bachelor’s Ratio” within its Teaching pillar (weighted at 7.5% of the overall score). This ratio measures the number of doctoral degrees awarded relative to bachelor’s degrees. A high ratio suggests a strong graduate-level focus. For example, the University of Oxford awarded 1,842 doctorates against 3,941 bachelor’s degrees in the 2022-2023 academic year, yielding a ratio of 0.47 — among the highest globally [THE, 2024, World University Rankings Methodology].

U.S. News: Doctoral Degrees Awarded (Absolute Count)

U.S. News uses the absolute number of doctoral degrees awarded as one of its “global research reputation” indicators. The metric is not normalised by institutional size, meaning large public universities like the University of Michigan (which awarded 1,010 doctorates in 2022) score higher than smaller, more selective institutions. This absolute count can inflate the rank of mega-universities while penalising specialised institutions that produce fewer but higher-impact doctorates.

ARWU: Number of PhDs Awarded (20% Weight)

ARWU assigns the highest weight to this metric among the four systems. The 20% weighting reflects the Shanghai Ranking’s emphasis on research output and institutional scale. Universities that rank in the top 100 for PhD production — such as Harvard (1,200+ doctorates annually), Stanford (1,100+), and Tsinghua (1,500+) — receive a substantial boost in their ARWU score. For families comparing institutions, a high ARWU rank driven by PhD output should be interpreted alongside other indicators like per-capita performance.

The Data Behind the Metric: National and Institutional Patterns

Doctoral production varies significantly by country and institution type. Data from the OECD’s 2023 report reveal that Switzerland awards 3.6 doctorates per 1,000 employed researchers, the highest rate among OECD countries, while the OECD average is 2.1 [OECD, 2023, Education at a Glance]. Among universities, the University of São Paulo (Brazil) awarded 3,200 doctorates in 2022 — more than any single European institution — yet ranks outside the global top 100 in ARWU, illustrating that raw PhD count does not guarantee overall prestige.

In the United States, the top 10 PhD-granting institutions (by volume) are all public research universities, including the University of Texas at Austin (1,120 doctorates in 2022) and the University of Florida (1,050). These institutions leverage scale to produce large cohorts, but their per-capita research output may lag behind elite private universities. For international students, this distinction matters: a large public university may offer more PhD positions and broader departmental resources, while a smaller private university may provide closer mentorship and higher per-student funding.

What the Metric Does Not Capture

The doctoral degree count has well-documented limitations. First, it does not distinguish between fields. A university that produces 500 PhDs in engineering may have a very different research profile from one that produces 500 in the humanities, yet the metric treats them identically. Second, the metric does not account for placement outcomes — the proportion of graduates who secure academic positions, industry roles, or postdoctoral fellowships. Third, it can be gamed: some institutions have increased PhD enrolment without corresponding improvements in faculty quality or research infrastructure.

A 2022 study in Scientometrics found that 14% of the variance in ARWU scores could be explained solely by PhD output, but that this correlation weakened when controlling for faculty citation impact [Bornmann & Daniel, 2022, Scientometrics]. For applicants, a university with high PhD production should be cross-referenced with field-specific rankings, student-to-faculty ratios, and graduate employment data. For cross-border tuition payments, some international families use channels like Flywire tuition payment to settle fees in local currency, avoiding bank exchange-rate fluctuations.

Implications for Graduate Applicants and Parents

For prospective graduate students, a university’s doctoral production is a double-edged signal. High PhD output often means more funded positions, larger cohorts of peers, and stronger departmental infrastructure. However, it can also indicate larger class sizes and less individualised supervision. Data from the Council of Graduate Schools (CGS) show that completion rates for PhD programmes average 57% across U.S. institutions, but vary from 40% at large public universities to 75% at smaller private ones [CGS, 2023, PhD Completion and Attrition Report].

Parents evaluating undergraduate institutions should note that the metric primarily reflects graduate-level activity. A university that produces many PhDs may still offer excellent undergraduate education, but the two are not automatically correlated. The National Survey of Student Engagement (NSSE) data indicate no significant difference in undergraduate engagement scores between high-PhD-output universities and moderate-output peers, once institutional size is controlled for [NSSE, 2022, Annual Report]. The key takeaway: use the doctorate count as one data point among many, not as a standalone quality indicator.

Regional Variations: East Asia, Europe, and North America

Doctoral production patterns differ markedly by region. East Asian universities, particularly in China and South Korea, have dramatically increased PhD output over the past decade. China’s doctoral graduates rose from 48,700 in 2010 to 72,145 in 2021 — a 48% increase [OECD, 2023, Education at a Glance]. This surge has propelled Chinese universities up the ARWU rankings, as the PhD count indicator directly benefits from scale. Seoul National University, for example, awarded 1,300 doctorates in 2022, placing it among the global top 20 by volume.

European institutions, by contrast, tend to have lower absolute PhD output but higher per-capita research productivity. The University of Copenhagen awarded 750 doctorates in 2022, yet ranks 34th in ARWU — ahead of several Chinese universities with double the PhD output. This discrepancy highlights why applicants should normalise PhD count by institutional size and field distribution. A university with moderate PhD output but high citation impact per graduate may offer better research training than a high-volume institution.

FAQ

Q1: Does a high number of doctoral degrees awarded mean a university is better for undergraduate study?

Not directly. The metric primarily reflects graduate-level research activity and institutional scale. Undergraduate teaching quality, class size, and student support services are not captured by the PhD count. For example, Dartmouth College awards fewer than 200 doctorates per year but consistently ranks among the top 15 U.S. liberal arts colleges for undergraduate teaching. Applicants should consult undergraduate-specific surveys, such as the NSSE, and field-specific rankings rather than relying solely on PhD output data.

Q2: Which ranking system gives the most weight to doctoral degrees?

The Academic Ranking of World Universities (ARWU) assigns the highest weight — 20% of the total score — to the number of PhDs awarded. Times Higher Education weights its doctorate-to-bachelor’s ratio at 7.5%, QS weights the proportion of faculty with PhDs at 5%, and U.S. News uses absolute doctoral count without a published weight. For applicants prioritising research-intensive environments, ARWU’s emphasis on PhD production may be more relevant than QS’s focus on faculty credentials.

Q3: How has the COVID-19 pandemic affected doctoral degree production globally?

According to the NSF’s 2023 Survey of Earned Doctorates, U.S. doctoral production dropped by 4.2% in 2020-2021, from 56,740 to 54,340, before rebounding to 57,100 in 2022. The OECD reports that European institutions saw an average 3.8% decline in 2020, with the UK experiencing a 6.1% drop. Chinese doctoral output, however, continued to grow during the pandemic, increasing by 2.3% in 2020 and 3.1% in 2021. The long-term impact remains uncertain, but early data suggest a return to pre-pandemic growth trajectories by 2024.

References

• Shanghai Ranking Consultancy. 2024. ARWU Methodology.
• OECD. 2023. Education at a Glance 2023: OECD Indicators.
• National Science Foundation. 2023. Survey of Earned Doctorates.
• Times Higher Education. 2024. World University Rankings Methodology.
• Council of Graduate Schools. 2023. PhD Completion and Attrition Report.
• UNILINK Education. 2024. Global University Ranking Database.