The “efficiency” criterion is more difficult to define, but here it means roughly “makes use of all the available information”
How do you know? Or, more explicitly, on the basis of which evidence are you willing to make the claim that consensus macro forecasts “make use of all the available information”?
Besides, just having information is necessary but not sufficient. You also need models which will take this information as inputs and will output the forecasts. These models can easily be wrong. Is the correctness of models used included in your definition of efficiency?
It is difficult to conclusively demonstrate efficiency, but it is easy to rule out specific ways that forecasts could be inefficient. That’s what the papers do.
How do you know? Or, more explicitly, on the basis of which evidence are you willing to make the claim that consensus macro forecasts “make use of all the available information”?
Besides, just having information is necessary but not sufficient. You also need models which will take this information as inputs and will output the forecasts. These models can easily be wrong. Is the correctness of models used included in your definition of efficiency?
It is difficult to conclusively demonstrate efficiency, but it is easy to rule out specific ways that forecasts could be inefficient. That’s what the papers do.