inadequate stimulus

sub·thresh·old stim·u·lus

a stimulus too weak to evoke a response.

in·ad·e·quate stim·u·lus

(in-ad'ĕ-kwăt stim'yū-lŭs)
A stimulus too weak to evoke a response.
References in periodicals archive ?
Presumably he would also say the stagnation of the 1930s was the result of inadequate stimulus, even though Hoover increased the burden of spending by about 50 percent in just four years and Roosevelt then doubled the budget in the next eight years.