# Plural and countability of the word 'performance'

Algorithms A and B provide good performance.

Algorithms A and B provide good performances.

Could you please tell me which one between the above sentences is correct ?

Algorithm A provides good performance.

Algorithm A provides a good performance.

Also, between the above sentences, which one is correct ? In other words, is performance countable or uncountable in this context?

Performance is uncountable in this context. So you want:

Algorithms A and B provide good performance.

and

Algorithm A provides good performance.

I do think this is the sort of thing where you might find some disagreement. Abstract nouns like "performance" and "speed" can be interpreted as quantifiable properties, or scores, in which case they would be countable.

The speeds of the two cars were 45 kph and 80 kph, respectively.

But you could also say of two football players (whatever the flavor of football)

Smith and Jones have excellent speed.

"Performance," in the sense of algorithm speed, is a fairly new term. It still sounds awkward to me to say "This table gives the performances of the different algorithms," even though it fits the pattern of the "speed" examples. But you will definitely find that phrasing in the scientific literature.

In the examples you gave, however, the non-countable forms are definitely preferred.

• Do you think it could be explained like this: Two footballer players have "one" speed (that is excellent speed), so, it's in singular. Two cars have two speeds (45 and 80), so it's in plural.
– Jan
Dec 14, 2019 at 9:19
• First of all, your comment reminds me that my term "football player" may not be as flexible as I imagined. People who play what I call "soccer" tend to be called "footballers", not "football players." But someone who plays American (or Canadian) football is never called a footballer. Dec 15, 2019 at 2:13
• I think I got interrupted and never answered the question you were asking in this comment. No, the two football players don't have "one" speed. "Speed" in this case is like water or sand. You can't have two waters - it just doesn't make sense. "Food" is like that too. You wouldn't say "those two restaurants have good foods". You would say they have good food. Aug 16, 2020 at 14:43