"Simple extrapolation" means making predictions or estimates based on existing data or trends by extending them in a straightforward way into the future. Full definition
That's why simple extrapolation of past patterns is not enough. (skepticalscience.com)
Nor did the model come anywhere close to an even simpler extrapolation of current behaviour, based on kinematics rather than dynamics. (environmentalresearchweb.org)
And we know that house prices can deviate in a meaningful way from underlying fundamentals, especially if expectations of price gains are based on simple extrapolations and become disconnected from economic fundamentals. (bankofcanada.ca)