It may be found that there is only an interaction effect present between one or a few of the variables. In the case of a 2x2 design, there will be six possible interactions: V1S1-V1S2, V1S1-V2S1, V1S1-V2S2, V1S2-V2S1, V1S2-V2S2, V2S1-V2S2.n statistics, an interaction variable is one of variables often used in regression analysis. It is formed by the multiplication of two independent variables. Usage of interaction variables, while offering some useful data, also raises the issues of multicollinearity.