Ron Guth:
Experts speculate that the 1914/3 Nickel was caused when a 1913 dated master die was repunched with a 1914 dated hub. This theory is supported by the fact that there are several different overdate dies, plus overdates reported for both the 1914-D and 1914-S Nickels. The strongest 1914/3 die from the Philadelphia mint is known as FS-101 (old FS-014.87). The closeup illustrated above is from a different die and shows doubling on all digits of the date, plus a fairly strong top of the 3. Value for this variety depends on the strength (visibility of the doubling). Thus, the FS-101 commands the highest premium. Other, less visible overdates command smaller premiums.