In: Psychology
What is the rationale for using random assignment in experimental group research designs? In other words, what benefit(s) does using random assignment have in a study? How is random assignment different from random selection?
Random assignment is an experimental procedure where participants are divided into the different treatment conditions with equal opportunity for being in either of the groups irrespective of variables such as race, gender, time, motivation factors, perosnality characteristics, etc. it therefore allows for a comparison between the Experimental group and the Control group. Because each participant had an equal chance of being placed in any group, it is unlikely the differences could be attributable to some other preexisting varibale of the participant due to chance other than the independent variable and it thus helps to determine the probability of a significant difference in the sample. E. g. those who arrived on time versus late would be compared on an equal plane.
Random assignment is different from random selection as the latter is a method of drawing a sample of participants from the population for inclusion in the study wherein every member of the population has an equal chance of being included in the sample. Random assignment on the other hand is an experimental design in which the generated sample of participants are divided into experimental and control groups.