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I am confused with the use of plural or singular with the word "performance".

My context is the following: I am running multiple experiments in order to evaluate the performance(s?) of an algorithm.

I want to say that using method A is not relevant to evaluate the algorithms in term of performance(s?).

In my native language (French), that would be plural, but I think the logic is different in English. Is it uncountable? Is it always the case?

In the sentences above, should I write performance or performances?

marked as duplicate by RyeɃreḁd, choster, tchrist, aedia λ, Mr. Shiny and New 安宇 Apr 30 '14 at 12:54

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    performances is used when referring to the plural of performance as in an act/play. When referring to the success of a process performance is a mass noun and takes the singular – msam Apr 23 '14 at 10:33
  • Voulez-vous dire "évaluer les performances de l'algorithme en chaque cas", ou "évaluer la performance de l'algorithme globalement"? Je pense que dans le premiere cas, en anglais il peut être pluriel, mais dans le deuxième il doit être singulier. (Please pardon my French as I haven't used it regularly for years.) Do you mean "to evaluate each instance of the algorithm in each instance", or "evaluate the general performance of the algorithm"? I think in the first case, it can be plural, but in the second it must be singular. – jimsug Apr 23 '14 at 13:38
  • @jimsug in both cases, I would use plural in French. But I guess, what I want to say is closer to the first sentence. – Maxime Apr 23 '14 at 14:46

Either "performance" or "performances" is possible but the meaning will be changed based on the choice.

"Evaluate the performance of the algorithm." means to judge how well the algorithm performs under various conditions. What is evaluated is the quality of the algorithm based on its performance.

"Evaluate the performances of the algorithm." means to watch the algorithm being carried out possibly before spectators more than once and judge each performance separately on its merits. The algorithm is not evaluated. What is evaluated are the performances possibly for skill or fidelity to the algorithm.

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    I don't think the latter necessitates spectators - you could have an algorithm run a hundred times in the bakcground/overnight, then evaluate its performances based on time taken, throughput, fidelity, etc. – jimsug Apr 23 '14 at 14:49
  • Spectators are not necessary but "possibly" present as I indicated merely for the purpose of explaining the distinction. – Aaron K Apr 23 '14 at 15:21

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