Counterbalance

Counterbalancing is a type of experimental design in which all possible orders of presenting the variables are included. For example, if you have two groups of participants (group 1 and group 2) and two levels of an independent variable (level 1 and level 2), you would present one possible order (group 1 gets level 1 while group 2 gets level 2) first and then present the opposite order (group 1 gets level 2 while group 2 gets level 1). This way you can measure the effects in all possible situations. Obviously there are limitations with this procedure as not all studies can be designed this way and as you increase the number of variables, conditions, etc., it just becomes logistically problematic.