**Merits**

The harmonic mean has the following merits.

- It is rigidly defined.
- It is based on all the observations of a series i.e. it cannot be calculated ignoring any item of a series.
- It is capable of further algebraic treatment.
- It gives better result when the ends to be achieved are the same for the different means adopted.
- It gives the greatest weight to the smallest item of a series.
- It can be calculated even when a series contains any negative value.
- It makes a skewed distribution a normal one.
- It gives a curve straighter than that of the arithmetic and geometric mean.

** Demerits**

However, the harmonic mean suffers from the following demerits.

- It is not easy to understand by a man of ordinary prudence.
- Its calculation is cumbersome as it involves finding out of the reciprocals of the numbers.
- It does not give better and accurate results when the means adopted are the same for the different ends achieved.
- Its algebraic treatment is very much limited and not far and wide as that of the arithmetic mean.
- It is greatly affected by the values of the extreme items.
- It can not be calculated, if any, of the items is zero.