"not effective enough" is a grammatically correct phrase that can be used in written English.
For example, "The current plan of action was not effective enough to produce the desired results."
Perhaps lipid-soluble antioxidants (carotenoids) are not effective enough and phenolics are not effectively extracted with oil.
The enhancement of sound insulation was not effective enough to increase the restorative effects of sleep.
All of the spaceships in the film were miniatures, as visual effects supervisors believed CGI was not effective enough to create realistic spaceships.
This concept may create new opportunities for delivery of conventional drugs that are not effective enough in vivo and/or display serious extrahepatic side-effects.
"For the most part, it is not effective enough.
But they're not effective enough, and also hit the poorest most.
Results show that the interpolation method is not effective enough to reflect the actual climate conditions for many sites.
The results showed that individual protective systems are not effective enough to mitigate the damage caused by blast loading.
Even disregarding the wrong models, the others still contain auxiliary unit resistors that cause models redundant and not effective enough.
Too many schools are still not effective enough, and that is a challenge for the profession as well as government.
Despite the fact that alternative paths could be selected at the source node to reach the same destination node, this is not effective enough to improve network performance.
