|Longitudinal data is used in statistical and financial studies. Longitudinal data analysis has become popular as one of statistical methods. The process of analyzing past return data for a given security is an example of using longitudinal data. The longitudinal data are defined as the data resulting from the observations of subjects (human beings, animals, or laboratory samples, etc). Scholarly journal is a peer-reviewed journal in which scholarship relating to a particular academic discipline is published. Scholarly journals serve as forums for the introduction and presentation for scrutiny of new research, and the critique of existing research. Content typically takes the form of articles presenting original research, review articles, and book reviews. The term Scholarly journal applies to scholarly publications in all fields; this article discusses the aspects common to all academic field journals.