NAD83, No Shift Required

For practical GIS applications, there is no difference between NAD83 and WGS84. Both are very precise measurements of the same thing, and what differences there are between the two are largely due to how the statistical noise was handled. Also, there are no published techniques or generally accepted means of converting from NAD83 to WGS84. The end result of all this is that this transformation currently does nothing. If, in the future, a generally accepted means of converting from NAD83 to WGS84 becomes available, the transformation will be modified to implement that technique.