Experimental research is a type of controlled research where one is trying to find causation. That is, there is manipulation of an independent variable to determine the effect on the dependent variable. To design a proper experimental investigation, a scientist should properly follow the steps in the scientific method. It is important to identify which variable in the experiment you wish to manipulate, which is called the manipulative or independent variable. The outcome, or what you will be measuring is known as the dependent or responding variable. The outcome "depends" on what you changed or "manipulated." When designing an experiment, one of the most important aspects is determining the constants. Constants are the other elements in the experiment that need to remain the same. Without constants, it is difficult to know if it was true manipulation of the independent variable that caused differences in outcomes, or if it was some other element. A control group must also be established. The control group is the group that receives no experiment which is used as a base line, or standard for comparison.