Not many homeowners are informed that there is more than a single method to arrange balusters for their newly built or renovated staircase.  There are at least three banister arrangement patterns to select from.  Depending on preference, one can pick the angled top – horizontal base, angled top – angled base, or the closed stringer arrangement. 
When using the angled top – horizontal base arrangement, the base of each baluster is parallel to the steps (horizontal) while the top of the baluster follows the angle of the handrail: this angle is termed the “rake” angle.  This style requires the turned portion of the baluster to increase as well as the baluster’s overall length.  The angled top – horizontal base is a fairly common arrangement.
The angled top – angled base baluster style is slightly different.  The baluster bases as well as the baluster tops match the rake angle.  Basically, the bases and tops are parallel to the rail.  Even though the overall baluster lengths vary, the shaped baluster lengths (the part between the squares) stay the same.
The closed stringer differs from the two prior designs in that the balusters do not actually attach to the treads.  A small “wall” rises above the treads and is parallel to the handrail (the rake angle).  The baluster bases are secured to this “wall”.  In this arrangement, the overall length and the shaped portion of the balusters are identical.  As in the last example, these baluster bases and tops follow the rake angle.
Aside from the banister arrangement it is important to discuss the number of banisters per step.  In most communities there is a four inch code.  This regulation states that a four inch sphere cannot be inserted between two balusters.  This safety condition averts a child from lodging her/her head between two balusters.  It is my opinion that many designers perfer two banisters per tread.  However, in order to observe local building constraints, designers and/or homeowners are obliged to employ three balusters.  The number of balusters will depend on the depth of the tread and the diameter of the baluster.  A greater baluster size or shallower step depth would mean a increased probability that two balusters can be installed.  Conversely, the smaller the size of the baluster and/or deeper the tread depth, the more likely that three balusters will be required.