So, is below sentence grammatically correct?
"It means that the higher the affective performance and ethic, the higher the level of individual performance is."
***** NOT A TEACHER *****
Good morning, wmac.
(1) I agree with IHIVG that your nice sentence needs another "the."
(2) Basically, I think (I could be very wrong) that your sentence is basically something like:
THE higher the moral principles, THE higher the level of individual performance.
(a) My books tell me this is a comparative type of sentence.
(b) It means something like:
The level of individual performance will go up higher to the extent that the moral principles practiced by that person continue to go up (rise/increase).
(3) This THE ... THE type of sentence is very popular in English. We can say things in a short and interesting way:
MR. SMITH: I want you to do something.
TOM: Yes, sir. Should I do it tomorrow, next week, or next month?
MR. SMITH: THE sooner, THE better. = It will be better for me if it is done as soon as possible.
MONA: I want to invite you to my party.
RALPH: Great! May I bring some friends with me?
MONA: Of course. THE more, THE merrier. = It will be merrier (more fun) to the extent that more people come.
Have a nice day!