The survey includes an "anxious index" that estimates the probability of a decline in real GDP.
[1] The survey began in 1968 and was conducted by the American Statistical Association (ASA) and the National Bureau of Economic Research (NBER).
[4][7][8] A 1997 analysis of density forecasts of inflation made in the SPF finds: "The probability of a large negative inflation shock is generally overestimated, and in more recent years the probability of a large shock of either sign is overestimated.
"[9] SPF keeps a record of the bias and error in its own past forecasts online.
[11][12][13][14] Studies have shown that professional survey forecasts can be biased, such as displaying pessimism or overconfidence.