After normal moveout corrections, it will be easy to see any residual 'jitter' between adjacent traces due to any remaining uncorrected statics errors, because the NMO correction should make all the reflections horizontal.
The remaining uncorrected statics errors may be due to errors at the shot points and at the geophone points.
These errors can be determined and separated using the SU package suresstat command, which performs a surface consistent source and receiver statics calculation.
Use the suresstat command to understand the residual static determination details.
The residual static errors should be removed before stacking all the gathered traces in order to produce the highest quality stack.