Edition V16N06 | Year 2011 | Editorial Online Article | Pages 33 to 35
Introduction: Reliable sample size and an appropriate analysis of error are important steps to validate the data obtained in a scientific study, in addition to the ethical and economic issues. Objective: To evaluate, quantitatively, how often the researchers of orthodontic science have used the calculation of sample size and evaluated the method error in studies published in Brazil and in the United States of America. Methods: Two major journals, according to CAPES (Brazilian Federal Agency for Support and Evaluation of Graduate Education), were analyzed through a hand search: Revista Dental Press de Ortodontia e Ortopedia Facial and the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO). Only papers published between 2005 and 2008 were examined. Results: Most of surveys published in both journals employed some method of error analysis, when this methodology can be applied. On the other hand, only a very small number of articles published in these journals have any description of how sample size was calculated. This proportion was 21.1% for the journal published in the United States (AJO-DO), and was significantly lower (p= 0.008) for the journal of orthodontics published in Brazil (3.9%). Conclusion: Researchers and the editorial board of both journals should drive greater concern for the examination of errors inherent in the absence of such analyses in scientific research, particularly the errors related to the use of an inadequate sample size.