# Name of the "We change something but everything else will remain unaffected" fallacy

Trying to find an established/formal term for this fallacy:

*“Right now we sell blue jeans for \$20 a pair, and we sell 10,000 pairs a month, earning \$200,000 a month. So if we increase our blue-jean prices to \$100 a pair, then we will earn \$1 million a month.”
*
The flaw being that if the price of blue jeans rises, customers will buy fewer of them, and so you won’t have simply quintupled your revenue by quintupling the product price.
Maybe…“inelastic behavior fallacy?”

I think of it as the Corporate Merger Press Release fantasy.

The name of the company changes, but of course price hikes and mass layoffs are not on the horizon.

I think this is the linear fallacy. Or linear behaviour fallacy.

The fallacy is that the revenue generated by selling jeans is simply a linear relationship:

revenue = price * constant

Whereas it is a much more complicated equation, with many variables.

When presented as an assumption, it’s sometimes called ceteris paribus, or “All else being equal.”

Also is there something like an extrapolation fallacy?
e.g. “We doubled our sales of foot spas last month. So, if we plot a graph, we see everyone on earth will own 10 foot spas by the end of next year!”

The opposite of which is ‘mutatis mutandis’.

It takes a lot of footspa to make a prediction like that.

In economics it is called the Lucas critique.