Necessity of "the"?

What is the necessity of the article "the" in the following two sentences?

"All the other variables are defined as above"

See reference: Carneiro, A., Portugal, P., & Varejão, J. (2014). Catastrophic job destruction during the Portuguese economic crisis. Journal of Macroeconomics, 39, 444-457.

"All other variables are defined as above"

See reference: Thornton, J., & Esposto, F. (2003). How important are economic factors in choice of medical specialty?. Health economics, 12(1), 67-73.

Both researches are published in academic journals, therefore, both are peer reviewed (and thus the reliability of those sentences has been verified). So, in this context, what's the difference?

Solution 1:

"All the other variables" implies that they are known and being referred to by using the word "the".

"All other variables" implies all variables, known, unknown, or that may someday be known. It sounds more like it's covering everything in existence.

If I had five automobiles and said, "Two are cars and all other automobiles are trucks," it would sound like every other automobile in the world is a truck.

Alternatively, if I say, "Two are cars and all the other automobiles are trucks," it refers more to a predefined set of cars.