The choice between using “compare with” versus ”compare to” has been subject to debate for years. While the distinction is often considered to be preferential and some publishers dictate a house style, grammarians tend to agree that there are actual distinctions.

The distinctions are related to both the intended meaning as well as to grammar. According to the Oxford University Press, in US English, the preference is generally “to,” while in UK English the two constructions are “more evenly spread.”

When you compare, you ‘estimate the similarity or difference between things.’

From the Oxford University Press

Individual schools compared their facilities with those of others in the area.

It is difficult to compare our results to studies conducted in the United States.

In this meaning, either preposition can be used.

However, when “compare” is used to say that one thing resembles another, or to make an analogy between two different things, “to” is obligatory:

Her novel was compared to the work of Daniel Defoe.

He compared children to young trees, both still growing and able to be shaped.

■

The well-known source Strunk and White says this (edited):

To “compare with” is mainly to point out differences between objects regarded as essentially of the same order.

To “compare to” is to point out or imply resemblances between objects regarded as essentially of a different order..

• Congress may be compared with the British Parliament.

• Thus, life has been compared to a pilgrimage, to a drama, to a battle.

• Paris has been compared to ancient Athens; it may be compared with modern London.

■

Another source, The Grammarist, says this:

“Compared with” is usually referring to two objects of similar classification (e.g., dogs to dogs and cats to cats). Within this similar order, the user is speaking of the differences between the two objects of comparison.

“Compared to” is referring to two items in different classifications (e.g., dogs to cats or cats to cars). In these differing classifications, the user is pointing out similarities between the two seemingly unrelated objects.

Whether you use “with” or “to” won’t be noticed by many readers. But if correctness is your goal, the safest bet is as follows:

Compare with (similar items):