Is it becoming harder to secure reviewers for peer review? A test with data from five ecology journals

Table 1 Summary of reviewer invitations and responses

	Mean number of reviews per manuscript:					Mean proportion of reviews completed (95 % CI)
Year	Invited	Declined	Unassigned	Uninvited	Completed
2009	5.68	2.76	0.23	0.14	2.69	0.47 (0.43 to 0.52)
2011	6.16	3.18	0.24	0.08	2.74	0.44 (0.41 to 0.49)
2013	6.74	3.77	0.19	0.05	2.78	0.41 (0.38 to 0.45)
2015	6.46	3.43	0.10	0.02	2.82	0.44 (0.40 to 0.48)

The table includes only original submissions that went out for peer review. Categories are invited (all reviewers who were invited regardless of whether they accepted and completed a review, declined, had an invalid email, or were unassigned); declined (reviewers who actively declined as well as those who did not respond, and those with invalid emails); unassigned (reviewers who accepted an invitation but were later unassigned, i.e., did not complete a review); uninvited (reviewers whose invitations were revoked before they responded); and completed (reviewers who returned a review after accepting an invitation). The last column gives the mean proportion of review invitations that lead to a review being completed

ISSN: 2058-8615