Table 1.
The 2-year citation averages for open access versus subscription journals, calculated using Web of Science or Scopus data
| Source | Type | Journals (n) | Journal level | Article level | ||
|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | |||
| Journal Citation Reports 2-year citation average | Subscription | 7,609 | 1.97 | 2.95 | 2.81 | 3.31 |
| Open access | 610 | 1.50 | 4.02 | 2.04 | 2.28 | |
| Scopus 2-year citation average | Subscription | 11,124 | 0.85 | 1.38 | 1.59 | 1.99 |
| Open access | 1,327 | 0.61 | 1.85 | 1.03 | 1.44 | |
In the journal level calculations each journal has equal weight; in the article level calculations the impact factors for the journals are weighted by their publication volumes.