What is the h-index? A Guide for African Researchers
Home › Open Access & Research Practice › Explainer Researcher Guide · Open Access One number is supposed to sum up a researcher’s whole career — how much they publish and how much it gets cited. That number is the h-index. Here is exactly what it means, how to work yours out, why three databases will give you three different answers, and why no committee should judge you by it alone. By the FRELIP Editorial Team · Open Access & Research Practice · Reviewed against Hirsch (2005), DORA & the Leiden Manifesto, 2026 1 number productivity + impact combined 3 values Scopus, Web of Science & Google Scholar differ Free Google Scholar shows yours 2005 introduced by physicist J. Hirsch What this guide covers What the h-index is — and why it matters How to calculate it (worked example) Where to find yours — and why the numbers differ What the h-index can’t tell you The African researcher’s context Using it responsibly & how FRELIP helps FRELIP fact-check report Sources What the h-index is — and why it matters The h-index is a single number that tries to capture two things at once: how much a researcher has published, and how often that work is cited. It was proposed in 2005 by the physicist Jorge E. Hirsch (hence its other name, the Hirsch index), and it has since become one of the most widely quoted figures in academic careers — appearing in CVs, grant reviews, and promotion files. The definition is precise: The h-index, defined A researcher has an h-index of h if h of their papers have each been cited at least h times — and their remaining papers have no more than h citations each. So an h-index of 20 means: 20 papers, each cited 20 or more times. The appeal is that it resists two kinds of distortion. A researcher can’t inflate it with one wildly-cited paper (that lifts the count by only one), and they can’t inflate it by publishing dozens of papers nobody cites (those never reach the threshold). It rewards sustained, cited output — which is exactly why evaluators reached for it. Understanding it matters because, fairly or not, this number will be read as shorthand for your standing as a researcher. How to calculate it (worked example) To find an h-index by hand, list every paper’s citation count from highest to lowest, then walk down the list until the citation count drops below the paper’s position number. The last position where citations still meet or beat the rank is the h-index. Take a researcher with seven papers cited 10, 8, 5, 4, 3, 2, 1 times: 10#1 · 10≥1 ✓ 8#2 · 8≥2 ✓ 5#3 · 5≥3 ✓ 4#4 · 4≥4 ✓ 3#5 · 3<5 ✗ 2#6 · stop 1#7 · stop The cut-off falls at position 4: four papers have at least 4 citations each, but there is no fifth paper with at least 5. h-index = 4. You will almost never need to do this manually — the databases compute it for you (see next section). But doing it once makes the number concrete, and shows why adding a brand-new paper, or picking up a few more citations on your lower-ranked work, is what actually nudges an h-index upward. Where to find yours — and why the numbers differ Three major databases each calculate an h-index — and they will give you three different numbers. This is not an error. Each database only counts the publications and citations it indexes, and their coverage differs enormously. Source Access Coverage & typical h-index Google Scholar Free — public profile Broadest net (journals, conferences, preprints, theses, repositories, and self-citations) → usually the highest h-index. Also shows the i10-index. Scopus (Elsevier) Subscription Curated journal set → intermediate value. Web of Science (Clarivate) Subscription Most selective coverage → usually the lowest h-index. Studies comparing the three find Google Scholar’s h-index runs, on average, roughly 1.4× a researcher’s Web of Science value, with Scopus a little above Web of Science — though the exact ratio varies by person and field, so treat those as tendencies, not constants. The practical upshot: always state which database an h-index came from. An “h-index of 12” is meaningless without knowing whether it is a (generous) Google Scholar figure or a (conservative) Web of Science one. The free route: a Google Scholar Profile You can see — and show — your own h-index for free by creating a Google Scholar Profile. It displays your h-index and your i10-index (the number of your publications with at least 10 citations each, a Google-Scholar-only metric), and updates automatically as citations accrue. For researchers without a Scopus or Web of Science subscription, this is the accessible option. What the h-index can’t tell you The h-index is useful, but a single number hides a great deal. Every one of these limitations is well established — and every committee member should know them. Limitation What it means for you It only ever rises The h-index never decreases, even if a researcher stops publishing. It measures accumulated standing, not current activity. It is field-dependent Citation cultures differ hugely — biomedicine cites far more than mathematics. An h-index of 15 can be exceptional in one field and average in another. Never compare across disciplines. It favours long careers Because it can only grow, senior researchers almost always out-score early-career ones. It penalises people with less “academic age.” It ignores your role It counts a paper the same whether you were sole author or fifteenth of twenty. Author position and contribution vanish. It can be gamed Excessive self-citation can inflate it, so the raw number isn’t tamper-proof. It flattens your best work Once a paper passes the h threshold, extra citations on it don’t help. A landmark 2,000-citation paper counts the same as one just over the line. Two variants try to patch specific gaps. The m-quotient (Hirsch’s own idea) divides the h-index by the number of years since your
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