ABSTRACT
This chapter introduces the experimental study, a scientific study assimilating the artificial laboratory setup utilized in social and behavioral sciences, education, and psychology. The early 20th-century researchers Thorndike, McCall, and Chapman (1916), McCall (1923), Fisher (1926), and Fisher (1950) had laid the groundwork for experimental study. This was followed by Campbell and Stanley (1963, 1969) who set the foundation of experimental and quasi-experimental designs for social and behavioral sciences. Campbell and Stanley defined experiment as the “portion of research in which variables are manipulated, and their effects upon other variables are observed” (p. 1). Reliability and validity are assured over time through replication and cross-validation. Since the 1970s, the advancement of statistical methods has greatly enhanced the chances of improving the experimental designs. The chapter addresses the purpose, method, controlling intra-subject differences, and validity and reliability problems. The chapter explains conventionally accepted experimental designs with specific measures to handle validity and reliability.
