Contemporary h-Index
Also known as: hc-index, time-weighted h-index, age-decayed h-index
The contemporary h-index, introduced by Sidiropoulos, Katsaros, and Manolopoulos in 2007, modifies Hirsch's h-index to reward recent scientific activity over old laurels. The plain h-index never decreases and treats a citation earned decades ago the same as one earned last year, so a researcher who has stopped publishing can coast on an aging body of work. The contemporary index assigns each paper an age-discounted score, multiplying its citation count by a factor that shrinks as the paper grows older, and then applies the usual h-index ranking criterion to these scores. The result distinguishes currently active, recently impactful researchers from those whose reputation rests on distant achievements.
Key highlights
- Rewards recent scientific activity and impact, distinguishing currently productive researchers from those resting on old work.
- Can decrease over time, breaking the plain h-index's monotonicity and reflecting changes in momentum.
- Keeps the familiar, interpretable h-index ranking form while adding a principled age-decay.
- Tunable decay parameters let evaluators control how strongly older work is discounted.
Intuition
This section is available to Pro members. Upgrade to Pro
How it works
This section is available to Pro members. Upgrade to Pro
When to use it
Use the contemporary h-index when you want an author metric that emphasizes recent productivity and impact rather than lifetime accumulation, for example when assessing whether a researcher is currently active and influential, or when comparing scientists whose careers are at different phases of momentum. It is valuable in settings where coasting on old work should not be rewarded, such as ongoing performance reviews. It requires reliable publication years in addition to citation counts, and the choice of decay parameters affects results, so it should be reported with its settings. Like all h-variants it is not field-normalized and should accompany, not replace, broader and qualitative assessment.
Strengths & limitations
- Rewards recent scientific activity and impact, distinguishing currently productive researchers from those resting on old work.
- Can decrease over time, breaking the plain h-index's monotonicity and reflecting changes in momentum.
- Keeps the familiar, interpretable h-index ranking form while adding a principled age-decay.
- Tunable decay parameters let evaluators control how strongly older work is discounted.
- Requires accurate publication years for every paper, an input the standard h-index does not need.
- Results depend on the chosen decay coefficient and exponent, which are conventions rather than universal constants.
- Not field-normalized, so it remains unfair across disciplines with different citation and publication rhythms.
- Can penalize researchers in slow-maturing fields whose important work accrues citations only after many years.
Common pitfalls
This section is available to Pro members. Upgrade to Pro
Applications
This section is available to Pro members. Upgrade to Pro
Frequently asked
How does the contemporary h-index differ from the standard h-index?
The standard h-index treats all citations equally regardless of when the cited paper was published, so it only grows over time. The contemporary h-index first multiplies each paper's citation count by an age-decay factor that shrinks as the paper gets older, then applies the usual h-index criterion to these discounted scores. As a result it emphasizes recent work and can decrease as a researcher's older papers age, reflecting current activity rather than lifetime accumulation.
What do the decay parameters gamma and delta control?
Each paper's contemporary score is its citation count times gamma divided by its age raised to the power delta. Gamma scales the overall weight and delta sets how steeply older papers are discounted; the larger delta is, the faster old work loses weight. Sidiropoulos and colleagues used default values that make a four-year-old paper retain about one unit of weight per citation. Because results depend on these settings, they should always be reported alongside the index.
When might the contemporary h-index be unfair?
In fields where important work matures slowly and accrues most of its citations only years after publication, aggressively discounting older papers can understate genuine impact. The index is also not field-normalized, so it cannot be compared fairly across disciplines with different citation rhythms. It is best used within a field, with disclosed decay parameters, and alongside the standard h-index and qualitative judgment.
Sources
- 1.Sidiropoulos, A., Katsaros, D., & Manolopoulos, Y. (2007). Generalized Hirsch h-index for disclosing latent facts in citation networks. Scientometrics, 72(2), 253-280.
- 2.Hirsch, J. E. (2005). An index to quantify an individual's scientific research output. Proceedings of the National Academy of Sciences, 102(46), 16569-16572.
You have read it. What now?
Cite this page
ScholarGate. (2026, June 23). Contemporary h-Index. ScholarGate. https://scholargate.app/bibliometrics/contemporary-h-index