Improvement analysis of article quality in World Journal of Gastroenterology during 2008-2012

Table 1 Literature indexes for papers published in World Journal of Gastroenterology between 2008 and 2012

Year	No. of papers	No. of references	Average No. of references	No. of self-citations in the journal	The mean No. of self-citations in each paper	Self-citation rate
2008	1112	40485	36.41	930	0.84	8.59%
2009	863	29458	34.13	767	0.89	6.02%
2010	813	29624	36.44	832	1.02	5.50%
2011	677	25878	38.22	758	1.12	4.47%
2012	944	37947	40.20	918	0.97	5.21%

Table 2 Co-author collaboration status in World Journal of Gastroenterology in 2008-2012

Year	Distribution of number of co-author articles											Total (articles)	Authors	Cooperation degree	Cooperation rate
	1	2	3	4	5	6	7	8	9	10	≥11
2008	49	96	91	147	154	167	111	121	63	42	71	1112	6501	5.85	95.59%
2009	28	66	100	102	139	107	107	74	46	38	56	863	5072	5.88	96.76%
2010	28	62	77	84	113	108	108	74	53	46	106	813	5037	6.20	96.56%
2011	21	46	63	77	103	87	100	96	29	25	30	677	4034	5.96	96.90%
2012	31	67	86	122	95	137	111	91	57	57	90	944	5956	6.31	96.72%
Total	157	337	417	532	604	606	537	456	248	208	353	4409	26600	6.03	96.44%

Table 3 Authors with 5 or more publications in World Journal of Gastroenterology between 2008 and 2012

Author	Institute	No. of papers of first authors	No. of papers of the communicating authors	No. of cited papers	Citation frequency
Freeman, Hugh James	Univ British Columbia Hosp, Canada	22	22	22	133
Tarantino, Giovanni	Univ Naples Federico II, Med Sch Naples, Italy	7	9	7	42
Ishikawa, Toru	Saiseikai Niigata Daini Hosp, Japan	7	7	5	20
Akbulut, Sami	Diyarbakir Educ and Res Hosp, Turkey	7	8	5	18
Hirasaki, Shoji	Sumitomo Besshi Hosp,and Kubo Hosp, Japan	7	8	6	27
Sporea, Ioan	Univ Med and Farm Timisoara, Romania	5	5	5	52
Katsinelos, Panagiotis	Cent Hosp, Greece	5	5	4	19
Lohsiriwat, Varut	Mahidol Univ, Siriraj Hosp, Thailand	5	5	5	48
Terada, Tadashi	Shizuoka City Shimizu Hosp, Japan	5	5	3	41
Sun, Long	Xiamen Univ, Affiliated Hosp 1, China	5	0	4	37
Lee, Tae Hoon	Soon Chun Hyang Univ, Coll Med, Cheonan Hosp, South Korea	5	2	4	9

Table 4 Distribution of the top 15 countries or regions in World Journal of Gastroenterology during 2008-2012

Country name	2008	2009	2010	2011	2012	Total	Percentage
China	361	276	290	240	365	1532	34.75%
Japan	121	74	80	52	107	434	9.84%
United States	94	79	74	49	69	365	8.28%
South Korea	60	62	45	51	74	292	6.62%
Italy	54	53	53	60	56	276	6.26%
Germany	34	26	28	28	20	136	3.08%
Turkey	48	33	19	19	12	131	2.97%
Spain	31	35	13	16	21	116	2.63%
Greece	30	15	18	15	7	85	1.93%
England	23	18	16	9	17	83	1.88%
France	20	12	14	8	13	67	1.52%
Brazil	15	12	12	8	19	66	1.50%
Canada	23	13	9	3	11	59	1.34%
Netherlands	17	9	12	7	9	54	1.22%
Thailand	13	5	11	6	11	46	1.04%
Total	1305	998	984	811	1176	3742	84.87%

Table 5 Main journals citing World Journal of Gastroenterology papers published between 2008 and 2012 n (%)

No.	Name of the citing journals	Quantity
1	World J Gastroenterol	1131 (5.69)
2	PLoS One	430 (2.16)
3	Dig Dis Sci	198 (1.00)
4	Gastrointest Endosc	180 (0.91)
5	J Gastroenterol Hepatol	171 (0.86)
6	Aliment Pharmacol Ther	147 (0.74)
7	Inflamm Bowel Dis	147 (0.74)
8	J Hepatol	138 (0.70)
9	Hepatogastroenterology	137 (0.69)
10	Endoscopy	122 (0.62)
11	Eur J Gastroenterol Hepatol	120 (0.60)
12	Hepatology	120 (0.60)
13	Gastroenterology	114 (0.57)
14	Am J Gastroenterol	110 (0.55)
15	Scand J Gastroenterol	108 (0.54)
	Total	3373 (16.97)

Table 6 Data comparisons of the 7 representative gastroenterology journals in 2012

Journal name	Articles published in 2012	Cooperation degree in 2012	Cooperation rate in 2012	Geographical distribution of authors	Ratio of articles contributed by domestic authors	2012 impact factor	Ranking of discipline impact factors	Self-citation rate in 2012
Am J Gastroenterol	190	7.50	94.74	32	United States 45.16	7.553	7	3.36
BMC Gastroenterol	165	7.35	98.79	36	China 21.21	2.11	42	2.6
Gastroenterology	278	10.55	97.48	44	United States 44.25	12.821	1	2.2
J Clin Gastroenterol	154	6.41	96.10	24	United States 38.96	3.203	23	3.1
J Gastroenterol	140	9.53	98.57	22	Japan 76.43	3.788	17	3.34
Scand J Gastroenterol	179	6.40	98.88	35	Sweden 21.79	2.156	40	3.29
World J Gastroenterol	944	6.31	96.72	58	China 35.67	2.547	34	5.21