Calculate Field-Normalized Citation Impact

Computes the Field-Normalized Citation Impact (FNCI) for each work in the corpus. FNCI normalises a work's citation count by the average citation count of all works in the same field and publication year.

Usage

sm_metric_fnci(
  corpus,
  classification = c("openalex_concepts", "mesh", "manual"),
  call = rlang::caller_env()
)

Arguments

corpus

An sm_corpus object.

classification

Character; the classification system used to assign works to fields. One of "openalex_concepts" (default), "mesh", or "manual".

call

Caller environment for error reporting.

Value

A tibble with columns work_id, field, year, cited_by_count, field_mean, and fnci.

Details

FNCI is defined as:

$$FNCI_i = \frac{C_i}{\bar{C}_{f,y}}$$

Where \(C_i\) is the citation count of work i and \(\bar{C}_{f,y}\) is the mean citation count of all works in field f published in year y.

An FNCI of 1.0 means the work is cited at the world average for its field-year. Values > 1.0 indicate above-average impact.

For "openalex_concepts", the highest-scoring level-0 concept from the concepts table is used. For "mesh", MeSH terms are used (requires MeSH data in concepts). For "manual", a field column must already exist in corpus$works.

References

Waltman, L., van Eck, N. J., van Leeuwen, T. N., Visser, M. S., & van Raan, A. F. J. (2011). Towards a New Crown Indicator: Some Theoretical Considerations. Journal of Informetrics, 5(1), 37–47. doi:10.1016/j.joi.2010.08.001

See also

Other metrics: sm_metric_collab_index(), sm_metric_disruption(), sm_metric_g_index(), sm_metric_h_index(), sm_metric_m_index(), sm_metric_novelty(), sm_metric_rcr(), sm_self_citation(), sm_summary_authors(), sm_summary_period(), sm_summary_sources(), sm_summary_works()

Examples

corpus <- sm_example_corpus()
fnci <- sm_metric_fnci(corpus, classification = "openalex_concepts")
head(fnci)
#> # A tibble: 6 × 6
#>   work_id    field                    year cited_by_count field_mean  fnci
#>   <chr>      <chr>                   <int>          <int>      <dbl> <dbl>
#> 1 W000000001 clinical outcomes        2023              3       10.2 0.293
#> 2 W000000002 colorectal cancer        2020              9       12.2 0.738
#> 3 W000000003 gene expression          2024             28       11.3 2.47 
#> 4 W000000004 spatial transcriptomics  2020             29       27.5 1.05 
#> 5 W000000005 immune checkpoint        2020             16       16   1    
#> 6 W000000006 immune checkpoint        2018             16       16   1