Educational Research and Reviews Vol. 6(1), pp. 110-123, January 2011 Available online at http://www.academicjournals.org/ERR ISSN 1990-3839 ©2011 Academic Journals Full Length Research Paper An educational dilemma: Are educational experiments working? Serhat Kocakaya Department of Physics Education, Faculty of Education, Yüzüncü Yıl University, 65080 Campus/Van, Turkey. E-mail:
[email protected],
[email protected]. Tel/Fax: 0432 2251024/0432 2251038. Accepted 23 December, 2010 The main aim of this study is to investigate the biased effects which affect scientific researches; although most of the researchers ignore them, and make criticism of the experimental works in the educational field, based on this viewpoint. For this reason, a quasi-experimental process has been carried out with five different student teachers groups, to see the John Henry effect which is one of those biased artifacts. At the end of the whole process, it was seen that the John Henry effect plays a great role on students’ achievements. At the end of the study, experimental works were discussed on the basis of those artifacts and some recommendations were presented on how we can reduce the effects of those artifacts or how we can use them to get benefit for our experimental works. Key words: Internal validity, bias effects, the John Henry effect. INTRODUCTION This study describes an unacknowledged artifact that Researches looking for evidence of whether group may confound experimental evaluations. The present teaching and video tutorial of CAI is a more effective study hypothesize that, the control group members method will typically find answers like ‘there is no perceiving the consequences of an innovation as difference’ (Taverner et al., 2000).