Which method can be used to find out strength

Which method can be used to find out strength of reductant/oxidant in a solution ? Explain with an example.

Measure the electrode potential of the given species by connecting the redox couple of the given species with standard hydrogen electrode. If it is positive, the electrode of the given species acts as reductant and if it is negative, it acts as an oxidant.
Find the electrode potentials of the other given species in the same’way, compare the values and determine their comparative strength as an reductant or oxidant. ,
Example Measurement of standard electrode potential of ${{Zn}^{2+}}$/Zn electrode using SHE as a reference electrode.