Message from Editors-in-Chief

Journal of Disaster Research (JDR) is a comprehensive, peer-reviewed professional journal published in Japan for studies on disaster reduction with all-hazard approach and has published more than 1,000 papers since 2006. I took over the chief editor from Dr. Takiguchi last September to help Dr. Murakami. I would like to keep working on publishing high-quality study achievements from JDR, as a clearinghouse site of disaster risk reduction and resilience information in Asia. I very much hope for your continued cooperation.

Kriteria Empirik dalam Menentukan Ukuran Sampel Pada Pengujian Hipotesis Statistika dan Analisis Butir

<p>Sample-size determination is often an important step in planning statistical study and item analysis and it is usually a difficult one. Among the important hurdles to surpassed, one must obtain an estimate of one or more error variances, and specify an effects size of importance. There is the temptation to take some shortcuts. This paper offers some suggestions for successful and meaningful sample-size determination. Also discussed is the possibility that sample-size may not be the main issue, that the real goal is to design a high-quality study. Finnaly, criticism is made of some ill-advised shortcuts relating to power and sample-size. <br /><br /></p>