The meaning is that the results you get by using a formula don't correspond well to actual data. Usually it means that you chose the wrong formula or the formula has some limitations. What is oxymoronic in that?
In short, stop trolling...
In Maths the above statement = fail
In Chem the above statement = fail
In Physics the above statement = fail
In Computer Science the above statement = fail
Even in sociology the above statement = fail
Economics is littered with examples of "formulas that don't correspond well to actual data". Then economists run a massive economic experiment called Quantitative Easing with these formulas...
It is hard to impossible to gauge human behavior (which is what economics is primarily concerned about) with strict mathematics. Also, wrong premises will lead to wrong conclusions which would not correlate with empirical data.
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