Managers must make decisions when data is unavailable or even impossible to collect.
A simple example is training. The only immediate evidence is its cost, expense. The effect of training will not be realized for months or even years in the future. Moreover, the effect can not be measured.
Then why does a company spend money for training? Because the management believe that there will in the future be benefits that far outweigh the cost. In other words, the management are guided by theory, not by figures. They are wise.
W. Edwards Deming, The New Economics for Industry, Government, Education – page 63
As Dr. Deming stated
It is wrong to suppose that if you can’t measure it, you can’t manage it – a costly myth.
page 10 of The New Economics.