The setback structures are quite common in modern buildings as they provide adequate ventilation of sunlight in congested areas. In addition, they fulfill the floor area ratio requirements specified by the Indian building code. Past earthquake reviews reveal inadequate seismic performance of back-up structures. Most seismic design codes quantify the irregularity of the setback ignoring gradual setback variation. Therefore, the effect of setback variation on the seismic response parameters must be studied. For achieving this purpose, building models with different setback configurations have been molded and analyzed by subjecting them to a set of 100 ground motions. The karvasilis approach was followed to find the various parameters of designing the structure and thus the response databank was prepared for the semi rigid, rigid and flexible type of connections. The multiple linear regression analysis was performed on the response databank and the equations for time period and behavior factor plus other parameters were formed. This helps in designing the structure more economically and safely with the implementation of these new equations