Important cases where the computational definition of R2 can yield negative values, depending on the definition used, arise where the predictions which are being compared to the corresponding outcomes have not been derived from a model-fitting procedure using those data, and where linear regression is conducted without including an intercept.

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The trouble is, while the definition of a recession as two consecutive quarters of negative growth is widely accepted, there is no popular definition of a depression, which means there is nowhere to go once recessions stop being relevant.

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If you go by the traditional definition of two quarters of negative growth, the United States avoided entering a recession in the first quarter, but only because of high inventories.

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