likelihood
Plurallikelihoods
- 1The chance that a particular outcome will occur; the degree to which something is probable.
Analysts weighed the likelihood of a market downturn before advising their clients.
Early treatment greatly increases the likelihood of a full recovery.
Similarprobability, chance, odds, possibility, prospect
Oppositeimprobability
Note
Built from likely plus -hood, already joined in Middle English as liklihode, so it names the quality of being likely. Its fixed phrase is in all likelihood, used like probably to frame a whole sentence. It also opens predictions as the likelihood is that…, and it takes of before what might happen: the likelihood of rain, your likelihood of success.
- 2The probability that a fixed set of observed data would arise from a random distribution with a particular parameter value.
Statisticians maximize the likelihood to find the parameter values that best explain the data.
The model with the greater likelihood was chosen as the better fit.
Note
In statistics the everyday question is turned around: the observed data are held fixed, and the parameter is what varies. Read that way, likelihood is a function of the parameter, and unlike a probability distribution it need not sum or integrate to one across parameter values. Hence the working phrase maximize the likelihood, which contrasts with the everyday sense of chance, where the outcome is what is uncertain.
- 3The quality of resembling something else, or the degree to which two things are alike.
Similarresemblance, similarity, likeness
Oppositedifference, dissimilarity
Note
The word read literally, as the state of being like. Walter Raleigh, in The Historie of the World (1614), could write that there is no likelihood between pure light and black darkness. Modern readers hear the probability meaning first, so a phrase like "a strong likelihood between the brothers" would be misread as a chance of something. For this idea, likeness or resemblance is the clear choice.
Less common meaning
- 4An outward appearance, show, or sign that indicates or promises something.
The boy gave every likelihood of becoming a fine scholar.
There was little likelihood of welcome in their cold faces.
Note
This sense is archaic and easy to mistake for a statement of odds. A boy who gave every likelihood of becoming a fine scholar showed promise, and no one calculated his chances. The sense suits historical fiction or deliberate period style. In ordinary prose, readers will hear the probability meaning, so appearance, sign or look is the safer choice when outward show is meant.
Practice
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Origin
From Middle English liklihode, formed from 'likely' plus the suffix '-hood'.