How do we describe "something that can be evaluated"? My first thought was "evaluatable", since we have

inflate  ->  inflatable
debate   ->  debatable
equate   ->  equatable

However, "evaluable" is apparently the word that means "able to be evaluated", not "evaluatable". Is there any particular reason for this apparent discrepancy, or is "evaluatable" actually okay?

Some quick notes

  • Estimable vs estimatable, invaluable vs invaluatable. compensable vs compensatable. There are more words that don't work that way. They are not discrepancies. – user140086 Feb 7 '16 at 11:51
  • @Rathony Thanks for the additional examples - I honestly didn't know estimate and compensate worked that way (although I don't think there's an "invaluate"?). That did lead to some interesting searches though, e.g. this question for "estimable" and this post for "compensatable", but I'm not sure what conclusion I should be drawing... – Sp3000 Feb 7 '16 at 12:18
  • My pleasure. I am glad I could help. – user140086 Feb 7 '16 at 12:21

In Google Books' database of published writings, the contest between evaluable (blue line) and evaluatable (red line) has not been close in recent years, as this chart for 1900–2005 indicates:

The earliest match for evaluatable that a Google Books search finds is from William Burton, The Guidance of Learning Activities: A Summary of the Principles of Teaching as Based Upon the Principles of Learning (1944) [combined snippets]:

Space is given here for two [specific illustrations]. The first illustration shows how general objectives are broken down into more specific measurable or evaluatable objectives. The material also demonstrates admirably the fact that objectives are actually progress goals to be achieved at different rates by different pupils.

The earliest legitimate match for evaluable appears to be from a poem titled "Tesla," in Reginald Robbins, Poems of Personality (1904):

So shall zeal/Establish zeal; insistently maintain/Mechanics which alone were mechanism/By fundamental faith. Else were despair/Indifferent; world indifferent, work to nought./Else were the fiery destruction, no/Undoing; nor the work evaluable./Else were world-service utterly inane.

But soon afterward, mathematical texts begin to use the word, as in Annals of Mathematics (1909):

This is a classic integral evaluable by means of the Γ—functions.

As a matter of pure speculation, I would guess that evaluable caught on in the first instance under the influence of valuable, which (because it comes from value) follows a different pattern from equate --> equatable and punctuate --> punctuatable. In any case, both evaluable and evaluatable are in use today—seemingly with the same meaning of "capable of being evaluated"—but the former is considerably more common than the latter.


I think for words with a penultimate vowel of 'a,' the '-able' suffix can be merged into the word. That's what I notice in all your examples: inflate, debate, equate, estimate, compensate, etc.


If evaluable is to be 'able to be evaluated", and evaluate is to be "able to be valued" then surely the correct word SHOULD be valuable? Admittedly we don't use it in this context very much....

  • The reason we don't use it in this context much is probably because "valuable" generally conveys "something of worth or value" instead of "possessing the ability to be evaluated." The question is therefore between "evaluable" and "evaluatable." In hard studies, namely maths and programming, I'd argue that "evaluatable" is more clear given logical operators and conditional/comparison evaluations. In non-academic pursuits, I'd probably default to the more common usage "evaluable" given @Sven's above answer. – Chad Dec 17 '19 at 21:12

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