A variable factor of production is one whose usage rate can be changed easily.

Possibly the most variable factor is you, the smallholder.

Normally a number of variable factors such as performance level and breed differences are taken into account.

More than a dozen variable factors could interact, with their permutations running into the thousands.

I conclude that there are more variable factors in the equation than were fully appreciated.

In fact, the plan depends on so many variable factors that it is difficult to predict the result with any certainty.

Of course, if someone did have an energy field sensible at 1 inch or 2 inches away, heat transfer would become a variable factor.

A variable factor is the speed difference between trains.

In the short run, a firm can raise output by increasing the amount of the variable factor(s), say labor through overtime.

The law of diminishing marginal returns to a variable factor applies to the short run.