Empirical Assessment of Effect of Publication Bias on a Meta-Analysis of Validity Studies on University Matriculation Examinations in Nigeria

Autor/in	Adeyemo, Emily Oluseyi
Titel	Empirical Assessment of Effect of Publication Bias on a Meta-Analysis of Validity Studies on University Matriculation Examinations in Nigeria
Quelle	In: World Journal of Education, 2 (2012) 3, S.57-65 (9 Seiten) PDF als Volltext kostenfreie Datei Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	1925-0746
Schlagwörter	Meta Analysis; Foreign Countries; Exit Examinations; Effect Size; Bias; Publications; Validity; Universities; Research; Hypothesis Testing; Statistical Significance; Nigeria + Suchen Sie Ihr Suchwort? Meta-analysis; Metaanalyse; Ausland; Final examination; Abschlussprüfung; Gültigkeit; University; Universität; Forschung; Hypothesenprüfung; Hypothesentest
Abstract	This study examined the impact of publication bias on a meta-analysis of empirical studies on validity of University Matriculation Examinations in Nigeria with a view to determine the level of difference between published and unpublished articles. Specifically, the design was an ex-post facto, a causal comparative design. The sample size consisted of 30 empirical studies selected on the basis of empirical status and relevance. The characteristics of these studies were recorded, coded and analyzed. The results revealed that the impact of publication bias was minimal on the meta-analysis study since the two versions, i.e. published and unpublished articles yielded essentially similar estimates of effect sizes. (Mean Fisher Zr = 0.393, Weighted Fisher WZr = 0.398 with associated r = 0.375 for both). Even though the use of non-representative proportion of significant studies in the two positive directions led to a non-representative set of studies, published articles had a higher effect size than the unpublished articles. (Zr = 0.460 for published, while Zr = 0.279 for unpublished). The effect size of published articles was significantly different from unpublished articles (X[superscript 2] = 5.42 p < 0.05 sig). This was an indication that studies with more significant results were the published. On the overall, there was no significant difference in the level of significance for both published and unpublished articles (X[superscript 2] = 0.0031 p > 0.05). Hence, publication bias did not affect the results of this meta-analysis. (As Provided).
Anmerkungen	Sciedu Press. 1120 Finch Avenue West Suite 701-309, Toronto, ON., M3J 3H7, Canada. Tel: 416-479-0028; Fax: 416-642-8548; e-mail: jct@sciedupress.com; Web site: http://www.sciedupress.com/journal/index.php/wje/index/
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2018/2/04