An expert in or an expert at?

An expert in or an expert at?

“In” and “at” are both prepositions.

There are over a hundred prepositions in English. They are almost always small and very common words. Prepositions usually tell us about the relationship between one word and another one. They might tell us about direction (such as “to”, “toward” or “down”), about time (such as “by”, “during” or “after”), or about location (such as “at”, “under” or “inside”).

Usually prepositions are single words, but they can also be groups of words (such as “close to” or “on top of”).

The most common prepositions include: about, above, across, after, along, at, before, behind, below, beside, between, by, despite, down, during, for, from, in, inside, into, near, of, off, on, on top of, onto, out of, outside, over, past, round, since, through, towards, under, until, up, with, within, without.

There is no strict rule about which preposition you should use with any particular situation. It really is a matter of reading and listening and getting to know what feels and sounds right.

As for expert in and expert at, both feel and sound right, so it doesn’t really matter which one you choose – they are interchangeable.

So:

• He is an expert in martial arts.
• He is an expert at martial arts.
• We need an expert in computer programming.
• We need an expert at computer programming.
• She is an expert in writing short stories.
• She is an expert at writing short stories.

In all these examples we are talking about people being experts in or at doing something. When the expertise is concerned with something more theoretical, then “expert on” might sound better.

For example:

• She is an expert on the paintings of Picasso.
• He is an expert on English grammar.
• They are experts on technopop.

Going back to an earlier example:

• He is an expert in martial arts,

and

• He is an expert at martial arts,

both tell us that he is good at performing martial arts.

If we say:

• He is an expert on martial arts,

we mean that he knows a great deal about martial arts. He might not be able to actually perform martial arts.

Using “expert about” might appear to make sense but these examples, just don’t sung right:

• I am an expert about classical music. (WRONG)
• We are experts about playing the guitar. (WRONG)
• He is an expert about model-making. (WRONG)

It would be better to say:

• I am an expert on classical music.
• We are expert at playing the guitar.
• He is an expert in model-making.

_{Posted by Graham}

_{With thanks to Lisa and Max for the idea.}