Cash Flow Earnings vs. Accrual Earnings
It turns out the the distinction is not so much between earnings or cash flow as it is between those earnings comprised of cash versus those comprised of accruals. Sloan highlighted that cash earnings are more persistent than accrual earnings, but the persistence of both earnings and cash flows varies with the level of accruals.
Earnings are more persistent than cash flows at each level of accruals, as shown by the gap between these two lines. However, where accruals are large, the persistence of earnings diminishes. i.e. earnings not backed by cash are not as reliable.
Deschow and Ge (2003)