RESUMO
Purpose: To test whether there is an association between the growth in the number of ophthalmic journals in the past years and their mean and maximum impact factor (IF) as a common sign of scientific proliferation. Methods: Using data from the 2013 Journal Citation Report database a study of the major clinical medical fields was conducted to assess the correlation between the number of journals and maximum IF in a given field in the year 2013. In the field of ophthalmology, we examined the correlation between year, number of journals, mean IF and maximum IF in the field of ophthalmology throughout the years 2000–2013. Results: In the major medical fields, a positive correlation was found between the number of journals and the maximum IF (quadratic R2 = 0.71, P < 0.001). When studying the field of ophthalmology a positive correlation between the number of journals and mean IF (R2 = 0.84, P < 0.001) and between number of journals and maximum IF (R2 = 0.71, P < 0.001) was detected. Conclusions: Our findings suggest that the variation in the IF can be explained by the number of journals in the field of ophthalmology. In the future, the formation of additional ophthalmology journals is likely to further increase the IFs of existing journals.
RESUMO
PURPOSE: The purpose of this study is to assess the validity and to review the errors of each category of inferential statistics used in Journal of Korean Ophthalmology Society (JKOS). METHODS: We reviewed 46 original articles of Journal of Korean Ophthalmology Society from January 2000 to March 2000 to assess 4 categories (the methods of statistical analysis, the way how to describe the statistical techniques, the validity of the used statistical techniques, and the interpretation of the results). RESULTS: With the types of statistics, comparison of mean was most commonly used (51.6%), followed by contingency table (16.1%), regression (15.1%), correlation (9.7%), and etc. (7.5%). With the way of describing the statistical techniques, 28 articles contained full description of every used statistical method, 15 had simply the list of statistical techniques, 2 had some methods omitted in description, and 1 was lack of explanation of statistical method. With the validity of the used statistical techniques, the most powerful statistical method was used in 66.7%, less powerful method in 8.6%, and improper method in 24.7% respectively. With the interpretation of the results, 26 articles drew correct conclusions via proper statistical method, 5 had errors in the interpretation of statistical results, 13 directed to incorrect conclusions due to improper statistical techniques, and 2 could not be judged due to omitted description of statistical method. CONCLUSIONS: We found that univariate or bivariate statistics rather than multivariate statistics were more preferred in JKOS, and authors should be more familiar with broad and precise knowledges of statistics.