Renáta Németh, Dávid Simon
Considerations: the level of measurement, the research focus and the shape of the distribution.
With nominal variable: mode.
With ordinal variable two choices, depending on the research focus. Most typical value: mode. Middle value: median.
With interval-ratio variable: three choices, depending on the research focus and the shape of the distribution.
Note that these are purely methodological considerations, not always followed in research practice. E.g. income data are usually skewed; however, the mean income is frequently used.