1. Have an effect on; make a difference to
"Sunlight exposure affects vitamin D production"
2. Touch the feelings of; move emotionally
"This painful experience affected him greatly"
3. Pretend to have or feel (something), often to make an impression on others
“She affected a sophisticated manner of speaking”
1. PSYCHOLOGY Emotion or desire as influencing behaviour
“The patient’s behavior indicated a negative affect”

How often is it used?

Impressively, the lemma affect is used nearly 3 million times in our database of scientific texts. This includes all inflections of the word, such as affects, affected, and affecting. While affect and affected are used more than 1 million times each, affects and affecting are each used less than half that number.

Affect occurs much more frequently in academic writing than in other genres. For example, it is 10 times more frequent in academic texts than in fiction writing (Corpus of Contemporary American English). The first meaning of ‘have an effect on; make a difference to’ is dominant in academia, although the noun form meaning ‘emotion or desire’ can be expected to be heavily represented in the field of psychology in particular.

Which words go with it?

The below chart shows the most common adverbs and nouns occurring with the verb affect in our scientific database of published papers. The thicker the line of each collocate, the more frequent it is.

Note that noun frequencies include all inflected forms (i.e. the node word measurements includes counts of measurement). Adverb collocations towards the top (e.g. dramatically, substantially) may be used to express a strong relationship, and those towards the bottom (e.g. slightly, hardly), a weaker one.

Which words can be used instead?

Words such as determine, decide, control, or influence are all possible synonyms of affect, as shown by our Language Search.

When comparing the use of affect and determine, the latter may appear less commonly used, as shown below. However, there is a slight difference between the two, with determine meaning to cause something to occur in a particular way rather than simply have an effect on it.

How to use affect in your academic text?

As shown in our analysis, it is very common for something to significantly or strongly affect results. For insights into the use of significant in academic writing, read our latest Word of the Month post here.

Make sure that the verb affect adequately expresses your factor-outcome interaction, or consider using synonyms such as determine or influence as alternatives. Also be aware that a very common mistake is to use the word effect when meaning affect, which is often used as a noun and has a very different meaning as a verb (i.e. to cause something to happen).

*Definitions from Oxford Languages

About the author

Mélodie is an Applied Linguist at Writefull.