• relative frequency, frequency per million [ statistics ]

    (also called freq/mill in the interface) a number of occurrences (hits) of an item per million tokens, also called i.p.m. (instances per million). It is used to compare frequencies between corpora of different sizes. number of hits : corpus size in millions of tokens = frequency per million The frequency per million is always related to the whole corpus or subcorpus, not to a text type. Restricting the query to one or more text types will affect the number of hits but the frequency per million will still be calculated using the number of tokens in the whole (sub)corpus. To relate the frequency per million to one or more text types, create a subcorpus from the text type(s) and restrict the query to this subcorpus.
    Example
    Looking up the frequency of the word helps in the British National Corpus (112,181,015 tokens), first in the spoken Text type and then in the spoken subcorpus will produce these results.
    SUBCORPUS SELECTED none none spoken 11,787,138 tokens
    TEXT TYPE SELECTED none spoken none
    HITS 3,116 302 302
    FREQUENCY PER MILLION 27.75 in relation to the number of tokens in the whole corpus 2.69 in relation to the number of tokens in the whole corpus 25.62 in relation to the number of tokens in the subcorpus
    POSSIBLE INTERPRETATION helps appears 27.75 times per million tokens in BNC ‘spoken’ helps appears 2.69 times per million tokens in BNC helps appears 25.62 times per million tokens in the spoken part of BNC
    see also Statistics in Sketch Engine Average Reduced Frequency