[fulafel]

That's not the definition.

Eg https://www.britannica.com/money/productivity says:

"productivity, in economics, the ratio of what is produced to what is required to produce it. Usually this ratio is in the form of an average, expressing the total output of some category of goods divided by the total input of, say, labour or raw materials."

[cjensen]

It's implied in the definition. Consider the units: a ratio should not have units. Lines of code per programmer per day would have weird units, for example, and could not be compared against number of windows installed per day for per car window installer. The only way for productivity to be useful is to normalize the inputs and outputs into money.