No economic numbers are reliable due to reflexivity - "reliable numbers" become inputs for policy makers and market participants, which drive changes in the economy that affect the previously "reliable numbers".<p>George Soros wrote extensive literature on the topic. He called his fund (second best performing hedge fund in history) the Quantum Fund because, according to him, true nature of economic reality is unknowable to humans. As in it is genuinely impossible to know, regardless of the amount of efforts.<p>Example: mortgage credit decisions depend on people's earnings and collateral value. Problem? Both earnings (salaries) and the collateral value (home prices) depend on the amount of credit in the system.<p>The economy, being a subset of psychology/sociology, cannot be understood via normal science because the level of understanding is not independent from the actual rules at work. I.e. the more we understand the different-er we behave. Unlike atoms, which don't care what humans think and just go about their own business.