1. The "economic index, Ce" is perfectly logical, but the slide contains non-standard definitions to trip up the unwary...

2. For _any_ size shell, the more meaty oysters also tend to have larger average diameter shells as they are more adult.

3. Sadly, you cannot tell just from the thickness of the shell how much oyster meat there will be inside the shell (and how much money you will get for it at market!).

4. Nor can you tell just from the mass how much oyster meat there will be inside the shell, as it may be very thick-shelled!

5. Since all oyster shells have the same general proportions, you do not have to worry about the height of the shell.

6. So all you have to do is normalise the shell's thickness by dividing by the shell's average diameter to estimate the potential economic value of the contained oyster meat.

Higher values of Ce do show HIGHER meat masses, and are therefore more economic to farm for meat...

So Raymond RaLonde's economic index would be right for MEAT BREEDING.

(Edits highlighted)

Thank You for explaining everything to me in detail. Can you please write me a complete formula with solid reference of the person who made it. I have to write it in my thesis and reference is very necessary. 

It will be every kind of you!

Dear Sadar, You may find my attached paper useful to cite. Best Regards, Ian Kennedy.

It's wonderful!!!

from a one simple question, how quickly you have made a perfect equation in a useful paper format. More than well done!!! Excellent! knowledge giant! 

and thank you for mention my name in acknowledgment, it means alot to me! 

Thank you!

Best Regards

Sadar