Scholars in different fields studied the issue of formulaic sequences, namely in general linguistics, corpus linguistics, phraseology, lexicography, psycholinguistics, neurolinguistics, first and second language acquisition and others.

Specialists in the areas of psycholinguistics and language acquisition draw on such criteria as familiarity with sequences by individual participants, and holistic storage of the sequences. Multiple production of the same sequence is used as evidence for the former criterion and intact intonation contour for the latter.

Schmitt and Carter (2004) suggest that both linguistic and psycholinguistic criteria should be applied to the definition of formulaic sequences. Besides the criteria named above, there are some other possible criteria used to identify when a word string is a formulaic sequence.

Each one of the criteria is presented separately below. The criteria are used in regard to form, meaning and use of multi-word sequences.